diff --git a/scripts/makefile.32sunu b/scripts/makefile.32sunu
index 430529b0b4de4a64e1d83d612af806a31e3c3bc5..517b97b4cbd28c628439f7634248ceacbc18a8a7 100644
--- a/scripts/makefile.32sunu
+++ b/scripts/makefile.32sunu
@@ -49,7 +49,7 @@ ZLIBINC=/usr/include
 WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 	-Wmissing-declarations -Wtraditional -Wcast-align \
 	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-CFLAGS=-I$(ZLIBINC) $(SUN_CC_FLAGS) \
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) $(SUN_CC_FLAGS) \
 	# $(WARNMORE) -g -DPNG_DEBUG=5
 LDFLAGS=$(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) libpng.a -lz -lm
 
diff --git a/scripts/makefile.64sunu b/scripts/makefile.64sunu
index 787d5a6f55fe57f664a3a6726eaa60fa4d509b6f..705b7e45b18475b8f54a5fb04b067eaabd08a308 100644
--- a/scripts/makefile.64sunu
+++ b/scripts/makefile.64sunu
@@ -49,7 +49,7 @@ ZLIBINC=/usr/include
 WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 	-Wmissing-declarations -Wtraditional -Wcast-align \
 	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-CFLAGS=-I$(ZLIBINC) $(SUN_CC_FLAGS) \
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) $(SUN_CC_FLAGS) \
 	# $(WARNMORE) -g -DPNG_DEBUG=5
 LDFLAGS=-L. -R. $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng14 -lz -lm
 
diff --git a/scripts/makefile.acorn b/scripts/makefile.acorn
index a0e577b245d635d9d676204cb3e53692ea35d39a..e2630d733eccab608fc80f8909e31e9011569163 100644
--- a/scripts/makefile.acorn
+++ b/scripts/makefile.acorn
@@ -2,7 +2,7 @@
 
 
 # Toolflags:
-CCflags = -c -depend !Depend -IC:,Zlib: -g -throwback  -DRISCOS  -fnah
+CCflags = -DPNG_CONFIGURE_LIBPNG -c -depend !Depend -IC:,Zlib: -g -throwback  -DRISCOS  -fnah
 C++flags = -c -depend !Depend -IC: -throwback
 Linkflags = -aif -c++ -o $@
 ObjAsmflags = -throwback -NoCache -depend !Depend
diff --git a/scripts/makefile.aix b/scripts/makefile.aix
index 262cafb070fc42c500e64ee5d171cdeef6355bd5..3dc6dbc37ee97ba481d5c17fe06ab0624090d32f 100644
--- a/scripts/makefile.aix
+++ b/scripts/makefile.aix
@@ -48,7 +48,7 @@ LDDEBUG =
 CRELEASE = -O2
 LDRELEASE = -s
 WARNMORE=-W -Wall
-CFLAGS = -I$(ZLIBINC) $(WARNMORE) $(CRELEASE)
+CFLAGS = -DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) $(WARNMORE) $(CRELEASE)
 LDFLAGS = -L. -L$(ZLIBLIB) -lpng14 -lz -lm $(LDRELEASE)
 
 # File extensions
diff --git a/scripts/makefile.amiga b/scripts/makefile.amiga
index 8bf0f455f1251cd431051e07eb019ae221fb36d8..6a64260ac849b408983dd25836dcbd1f31179817 100644
--- a/scripts/makefile.amiga
+++ b/scripts/makefile.amiga
@@ -15,7 +15,7 @@ CC=sc
 #compiler flags
 # WARNING: a bug in V6.51 causes bad code with OPTGO
 #          So use V6.55 or set NOOPTGO!!!!!!!!!
-CFLAGS= NOSTKCHK PARMS=REG OPTIMIZE OPTGO OPTPEEP OPTINLOCAL OPTINL\
+CFLAGS= -DPNG_CONFIGURE_LIBPNG NOSTKCHK PARMS=REG OPTIMIZE OPTGO OPTPEEP OPTINLOCAL OPTINL\
 	OPTLOOP OPTRDEP=4 OPTDEP=4 OPTCOMP=4 INCLUDEDIR=$(ZLIB) \
 	DEFINE=PNG_INTERNAL
 #linker flags
diff --git a/scripts/makefile.atari b/scripts/makefile.atari
index df841e597ec4ee06e9828b3f4979b6144bdee2eb..04f4b35d5161412c2a0684cc74ef3c9d4b5a1c66 100644
--- a/scripts/makefile.atari
+++ b/scripts/makefile.atari
@@ -9,7 +9,7 @@
 # modified for LC56/ATARI assumes libz.lib is in same dir and uses default
 # rules for library management
 #
-CFLAGS=-I..\zlib -O
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I..\zlib -O
 LBR = png.lib
 LDFLAGS=-lpng -lz -lm
 
diff --git a/scripts/makefile.bc32 b/scripts/makefile.bc32
index 64a3fe7f1e6394fbe1b8c20478f569e2b20b20bd..29d7686c90b4aff5bb1929a9f71f20e074159c1f 100644
--- a/scripts/makefile.bc32
+++ b/scripts/makefile.bc32
@@ -43,7 +43,7 @@ LDEBUG=$(LDEBUG) -N
 # -d  merge duplicate strings
 # -k- turn off standard stack frame
 # -w  display all warnings
-CFLAGS=-I$(ZLIB_DIR) -O2 -d -k- -w $(TARGET_CPU) $(CDEBUG)
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIB_DIR) -O2 -d -k- -w $(TARGET_CPU) $(CDEBUG)
 
 # -M  generate map file
 LDFLAGS=-L$(ZLIB_DIR) -M $(LDEBUG)
diff --git a/scripts/makefile.beos b/scripts/makefile.beos
index 88123d958a86d4025d5a3098fb1431e657a3ec76..836f9d0c2ba8bcf288aef11aa83a5d217a729b9a 100644
--- a/scripts/makefile.beos
+++ b/scripts/makefile.beos
@@ -44,7 +44,7 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 
 # On BeOS, -O1 is actually better than -O3.  This is a known bug but it's
 # still here in R4.5
-CFLAGS=-I$(ZLIBINC) -W -Wall -O1 -funroll-loops \
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -W -Wall -O1 -funroll-loops \
 	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5
 # LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng -lz
 LDFLAGS=-L. -Wl,-soname=$(LIBSOMAJ) -L$(ZLIBLIB) -lz
diff --git a/scripts/makefile.bor b/scripts/makefile.bor
index cabdf14098c8f2e3d5329384eff7c49523adf2a6..696f8efe185ea2c5b4eecdbc29834fb2210ec5af 100644
--- a/scripts/makefile.bor
+++ b/scripts/makefile.bor
@@ -51,7 +51,7 @@ LDEBUG=$(LDEBUG) -N
 # -w  set all warnings on
 # -O2 optimize for speed
 # -Z  global optimization
-CFLAGS=-O2 -Z -X- -w -I$(ZLIB_DIR) -$(TARGET_CPU) $(MODEL_ARG) $(CDEBUG)
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -O2 -Z -X- -w -I$(ZLIB_DIR) -$(TARGET_CPU) $(MODEL_ARG) $(CDEBUG)
 
 # -M  generate map file
 LDFLAGS=-M -L$(ZLIB_DIR) $(MODEL_ARG) $(LDEBUG)
diff --git a/scripts/makefile.cygwin b/scripts/makefile.cygwin
index da2ec68691e0f80db4cf743a26138a2b0be338cf..3ec0fb330a4ac8216711133fb845f6e35b6c2a8d 100644
--- a/scripts/makefile.cygwin
+++ b/scripts/makefile.cygwin
@@ -36,7 +36,7 @@ DESTDIR=
 
 CC=gcc
 ifdef MINGW
-MINGW_CCFLAGS=-mno-cygwin -I/usr/include/mingw
+MINGW_CCFLAGS=-DPNG_CONFIGURE_LIBPNG -mno-cygwin -I/usr/include/mingw
 MINGW_LDFLAGS=-mno-cygwin -L/usr/lib/mingw
 endif
 
diff --git a/scripts/makefile.darwin b/scripts/makefile.darwin
index 68280f8d05cdf6745f3505d11e71ed0cef38dda6..a2a6d5d83829ebea53be073886c2754f80abdafc 100644
--- a/scripts/makefile.darwin
+++ b/scripts/makefile.darwin
@@ -41,8 +41,8 @@ LN_SF=ln -sf
 RANLIB=ranlib
 RM_F=/bin/rm -f
 
-# CFLAGS=-I$(ZLIBINC) -W -Wall -O3 -funroll-loops
-CFLAGS=-I$(ZLIBINC) -W -Wall -O -funroll-loops
+# CFLAGS=--DPNG_CONFIGURE_LIBPNG I$(ZLIBINC) -W -Wall -O3 -funroll-loops
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -W -Wall -O -funroll-loops
 LDFLAGS=-L. -L$(ZLIBLIB) -lpng14 -lz
 
 INCPATH=$(prefix)/include
diff --git a/scripts/makefile.dec b/scripts/makefile.dec
index 9f5ccaa8160d5cc3ede0d2c1f85bccb2407af01f..6aee8aba652ae89cfd27d669ec083c3882b1af6e 100644
--- a/scripts/makefile.dec
+++ b/scripts/makefile.dec
@@ -57,7 +57,7 @@ DM=$(DESTDIR)$(MANPATH)
 ZLIBLIB=../zlib
 ZLIBINC=../zlib
 
-CFLAGS=-std -w1 -I$(ZLIBINC) -O # -g -DPNG_DEBUG=1
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -std -w1 -I$(ZLIBINC) -O # -g -DPNG_DEBUG=1
 LDFLAGS=-L$(ZLIBLIB) -rpath $(ZLIBLIB) libpng.a -lz -lm
 
 OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
diff --git a/scripts/makefile.dj2 b/scripts/makefile.dj2
index 021e969cfd52179dfbf6187eb6d35effc6d6f94a..86ca5c4607b274b3cd46e346f4dc45dd9e266b55 100644
--- a/scripts/makefile.dj2
+++ b/scripts/makefile.dj2
@@ -13,7 +13,7 @@ INCPATH=$(prefix)/include
 LIBPATH=$(prefix)/lib
 
 CC=gcc
-CFLAGS=-I../zlib -O
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I../zlib -O
 LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
 
 RANLIB=ranlib
diff --git a/scripts/makefile.elf b/scripts/makefile.elf
index 6fd5b560d4599b12a84a420ff1b19297cb70b4d9..6eefa9758f32ae3d08f34368908c0da9bce48413 100644
--- a/scripts/makefile.elf
+++ b/scripts/makefile.elf
@@ -57,7 +57,7 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 
 # for pgcc version 2.95.1, -O3 is buggy; don't use it.
 
-CFLAGS=-W -Wall -D_REENTRANT -O2 \
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -W -Wall -D_REENTRANT -O2 \
 	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5
 
 LDFLAGS=-L. -lpng14
diff --git a/scripts/makefile.freebsd b/scripts/makefile.freebsd
index 0243c952a346bf614b7a0eb956682e10b9c10187..2f2f1dda608f1a0a74a8287863a9cddbc3fb57dc 100644
--- a/scripts/makefile.freebsd
+++ b/scripts/makefile.freebsd
@@ -27,7 +27,7 @@ SYMLINKS=       libpng/png.h ${INCSDIR}/../png.h \
 LDADD+=         -lm -lz
 DPADD+=         ${LIBM} ${LIBZ}
 
-CFLAGS+= -I.
+CFLAGS+= -DPNG_CONFIGURE_LIBPNG -I.
 
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
diff --git a/scripts/makefile.gcc b/scripts/makefile.gcc
index f3365f729d4bc39dac9a8cfe86d78ab5083db35b..ac53601aab0e3a10ff7882c683f2499fb7304d55 100644
--- a/scripts/makefile.gcc
+++ b/scripts/makefile.gcc
@@ -22,8 +22,8 @@ CDEBUG = -g -DPNG_DEBUG=5
 LDDEBUG =
 CRELEASE = -O2
 LDRELEASE = -s
-#CFLAGS = -W -Wall $(CDEBUG)
-CFLAGS = -W -Wall $(CRELEASE)
+#CFLAGS = -DPNG_CONFIGURE_LIBPNG -W -Wall $(CDEBUG)
+CFLAGS = -DPNG_CONFIGURE_LIBPNG -W -Wall $(CRELEASE)
 #LDFLAGS = $(LDDEBUG)
 LDFLAGS = $(LDRELEASE)
 LIBS = -lz -lm
diff --git a/scripts/makefile.hp64 b/scripts/makefile.hp64
index c22b28fadbe2d32cd41a2aa014eb6925b3d3a38f..c58c1b32e65da0f32eaf838d34360a8ea4ef1a86 100644
--- a/scripts/makefile.hp64
+++ b/scripts/makefile.hp64
@@ -14,7 +14,7 @@ ZLIBINC=/opt/zlib/include
 # Note that if you plan to build a libpng shared library, zlib must also
 # be a shared library, which zlib's configure does not do.  After running
 # zlib's configure, edit the appropriate lines of makefile to read:
-#   CFLAGS=-O1 -DHAVE_UNISTD -DUSE_MAP -fPIC \
+#   CFLAGS=-DPNG_CONFIGURE_LIBPNG -O1 -DHAVE_UNISTD -DUSE_MAP -fPIC \
 #   LDSHARED=ld -b
 #   SHAREDLIB=libz.sl
 
@@ -40,10 +40,10 @@ LN_SF=ln -sf
 RANLIB=ranlib
 RM_F=/bin/rm -f
 
-CFLAGS=-I$(ZLIBINC) -O -Ae -Wl,+vnocompatwarnings +DD64 \
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -O -Ae -Wl,+vnocompatwarnings +DD64 \
 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 +Z -DHAVE_UNISTD_H -DUSE_MMAP
 # Caution: be sure you have built zlib with the same CFLAGS.
-CCFLAGS=-I$(ZLIBINC) -O -Ae -Wl,+vnocompatwarnings +DD64 \
+CCFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -O -Ae -Wl,+vnocompatwarnings +DD64 \
 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 +Z -DHAVE_UNISTD_H -DUSE_MMAP
 
 LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
diff --git a/scripts/makefile.hpgcc b/scripts/makefile.hpgcc
index fd031f18cfaedab991494f672302259645082473..bd1bf21e33bfb90eabf6c68e78e93af572256fce 100644
--- a/scripts/makefile.hpgcc
+++ b/scripts/makefile.hpgcc
@@ -56,7 +56,7 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 
 # for pgcc version 2.95.1, -O3 is buggy; don't use it.
 
-CFLAGS=-I$(ZLIBINC) -W -Wall -O3 -funroll-loops -DPNG_NO_MMX_CODE \
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -W -Wall -O3 -funroll-loops -DPNG_NO_MMX_CODE \
 	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5
 #LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng14 -lz -lm
 LDFLAGS=-L. -L$(ZLIBLIB) -lpng14 -lz -lm
diff --git a/scripts/makefile.hpux b/scripts/makefile.hpux
index d6d5c420169c1777c7c4a1b1a0024b98a5f6ab6f..adfa18aa4b7dde487a78ab39c1ab41d7be041562 100644
--- a/scripts/makefile.hpux
+++ b/scripts/makefile.hpux
@@ -48,9 +48,9 @@ LIBPATH=$(exec_prefix)/lib
 MANPATH=$(prefix)/man
 BINPATH=$(exec_prefix)/bin
 
-CFLAGS=-I$(ZLIBINC) -O -Ae +DA1.1 +DS2.0
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -O -Ae +DA1.1 +DS2.0
 # Caution: be sure you have built zlib with the same CFLAGS.
-CCFLAGS=-I$(ZLIBINC) -O -Ae +DA1.1 +DS2.0
+CCFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -O -Ae +DA1.1 +DS2.0
 LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
 
 # override DESTDIR= on the make install command line to easily support
diff --git a/scripts/makefile.ibmc b/scripts/makefile.ibmc
index 3b2525821806a1b21f86938a71e983d3684b94a5..7232d8fbb7d1e02684606503ac148c9432eed5ec 100644
--- a/scripts/makefile.ibmc
+++ b/scripts/makefile.ibmc
@@ -23,7 +23,7 @@ LD = ilink
 AR = ilib
 RM = del
 
-CFLAGS = -I$(ZLIBINC) -Mc -O2 -W3
+CFLAGS = -DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -Mc -O2 -W3
 LDFLAGS =
 
 # File extensions
diff --git a/scripts/makefile.intel b/scripts/makefile.intel
index fb705e121dedbccaf5269337cfe03752f2b689bb..498561c09f38d5f236fb05d5d27c87cb55e36b07 100644
--- a/scripts/makefile.intel
+++ b/scripts/makefile.intel
@@ -32,7 +32,7 @@ CALLING=r	# __fastcall
 # --------------------------------------------------------------------------
 
 CC=icl -c
-CFLAGS=-O2 -G$(CPU)$(CALLING) -Qip -Qunroll4 -I$(ZLIBINC) -nologo
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -O2 -G$(CPU)$(CALLING) -Qip -Qunroll4 -I$(ZLIBINC) -nologo
 LD=link
 LDFLAGS=/SUBSYSTEM:CONSOLE /NOLOGO
 
diff --git a/scripts/makefile.knr b/scripts/makefile.knr
index 75cb1b58aab88550ca583fb9fdbce10c4113e1c8..59bc2bcb3e86f28e05c4545453b48160ac054d30 100644
--- a/scripts/makefile.knr
+++ b/scripts/makefile.knr
@@ -27,7 +27,7 @@ LIBPATH=$(prefix)/lib
 DESTDIR=
 
 CC=cc
-CFLAGS=-I../zlib -O
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I../zlib -O
 LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
 # flags for ansi2knr
 ANSI2KNRFLAGS=
diff --git a/scripts/makefile.linux b/scripts/makefile.linux
index 3d49e1252cd68a7384e063aa0d0dfc907139a8db..9d030aecaa39c06bb2499fb3bf905a55bb575641 100644
--- a/scripts/makefile.linux
+++ b/scripts/makefile.linux
@@ -51,7 +51,7 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 
 # for pgcc version 2.95.1, -O3 is buggy; don't use it.
 
-CFLAGS=-I$(ZLIBINC) -W -Wall -O3 -funroll-loops \
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -W -Wall -O3 -funroll-loops \
 	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5
 
 LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng14 -lz -lm
diff --git a/scripts/makefile.mingw b/scripts/makefile.mingw
index 9b48c900f74d66d682b9e2842caf255bf52f1b6e..c88006e18c8b5ae88d1cc7d27ad312a94734daa0 100644
--- a/scripts/makefile.mingw
+++ b/scripts/makefile.mingw
@@ -61,7 +61,7 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 	-Wmissing-declarations -Wtraditional -Wcast-align \
 	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
 
-CFLAGS= $(strip $(MINGW_CCFLAGS) $(addprefix -I,$(ZLIBINC)) \
+CFLAGS= -DPNG_CONFIGURE_LIBPNG $(strip $(MINGW_CCFLAGS) $(addprefix -I,$(ZLIBINC)) \
         -W -Wall -O3 $(ALIGN) -funroll-loops \
 	-fomit-frame-pointer) # $(WARNMORE) -g -DPNG_DEBUG=5
 
diff --git a/scripts/makefile.mips b/scripts/makefile.mips
index 5e1040ed4ce72066cd97b6dca961fdb46cdd6ff0..21a9ca68428d56989fe4551bc69c4e81cf45a68c 100644
--- a/scripts/makefile.mips
+++ b/scripts/makefile.mips
@@ -22,8 +22,8 @@ LIBPATH=$(prefix)/lib
 DESTDIR=
 
 CC=cc
-CFLAGS=-I../zlib -O -systype sysv -DSYSV -w -Dmips
-#CFLAGS=-O
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I../zlib -O -systype sysv -DSYSV -w -Dmips
+#CFLAGS=-DPNG_CONFIGURE_LIBPNG -O
 LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
 
 #RANLIB=ranlib
diff --git a/scripts/makefile.msc b/scripts/makefile.msc
index 8ae8e61716c992ed42c02f0bc81c86950df4b35c..7fdc37fc56bfdbf93e3757af8564aa31d42edda8 100644
--- a/scripts/makefile.msc
+++ b/scripts/makefile.msc
@@ -10,7 +10,7 @@
 
 # -------- Microsoft C 5.1 and later, does not use assembler code --------
 MODEL=L
-CFLAGS=-Oait -Gs -nologo -W3 -A$(MODEL) -I..\zlib
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -Oait -Gs -nologo -W3 -A$(MODEL) -I..\zlib
 #-Ox generates bad code with MSC 5.1
 CC=cl
 LD=link
diff --git a/scripts/makefile.nommx b/scripts/makefile.nommx
index d612d6a340f786fc7135dd593137f031b406cea4..d1a26a94094eb130a5b592faa302f3a5c8215c09 100644
--- a/scripts/makefile.nommx
+++ b/scripts/makefile.nommx
@@ -51,7 +51,7 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 
 # for pgcc version 2.95.1, -O3 is buggy; don't use it.
 
-CFLAGS=-I$(ZLIBINC) -W -Wall -O3 -funroll-loops \
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -W -Wall -O3 -funroll-loops \
 	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5
 
 LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng14 -lz -lm
diff --git a/scripts/makefile.openbsd b/scripts/makefile.openbsd
index 1d21fd82c6efb88a57c62905f59f30634f2eada7..736fb6de83107c6b59752fd29317fc746ea2c44a 100644
--- a/scripts/makefile.openbsd
+++ b/scripts/makefile.openbsd
@@ -20,7 +20,7 @@ SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
 
 HDRS=	png.h pngconf.h
 
-CFLAGS+= -W -Wall
+CFLAGS+= -DPNG_CONFIGURE_LIBPNG -W -Wall
 CPPFLAGS+= -I${.CURDIR}
 
 NOPROFILE= Yes
diff --git a/scripts/makefile.os2 b/scripts/makefile.os2
index affb03c1a765cd65ff8ac1dd13aad0e0873423bd..e3fd36d7777a7e8ee26badf719dc45ff80278e33 100644
--- a/scripts/makefile.os2
+++ b/scripts/makefile.os2
@@ -15,7 +15,7 @@ ZLIBINC=../zlib
 WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 	-Wmissing-declarations -Wtraditional -Wcast-align \
 	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-CFLAGS=-I$(ZLIBINC) -W -Wall -O6 -funroll-loops -malign-loops=2 \
+CFLAGS=--DPNG_CONFIGURE_LIBPNG I$(ZLIBINC) -W -Wall -O6 -funroll-loops -malign-loops=2 \
 	-malign-functions=2 #$(WARNMORE) -g -DPNG_DEBUG=5
 LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lzdll -Zcrtdll
 AR=emxomfar
diff --git a/scripts/makefile.sco b/scripts/makefile.sco
index cfe8a3ae5478c897bc41fff8d8888a9249ce6df7..59e49e0203275f5bbec558b48e9b3568bbedcd29 100644
--- a/scripts/makefile.sco
+++ b/scripts/makefile.sco
@@ -41,7 +41,7 @@ exec_prefix=$(prefix)
 ZLIBLIB=../zlib
 ZLIBINC=../zlib
 
-CFLAGS= -dy -belf -I$(ZLIBINC) -O3
+CFLAGS= -DPNG_CONFIGURE_LIBPNG -dy -belf -I$(ZLIBINC) -O3
 LDFLAGS=-L. -L$(ZLIBLIB) -lpng14 -lz -lm
 
 INCPATH=$(prefix)/include/libpng
diff --git a/scripts/makefile.sggcc b/scripts/makefile.sggcc
index f4f5344b828becfdd45e2a9099e089c4c82c323e..baca87a5ef7a8edbfa111339711ae6d83fa7ed74 100644
--- a/scripts/makefile.sggcc
+++ b/scripts/makefile.sggcc
@@ -47,7 +47,7 @@ ZLIBINC=../zlib
 ABI=
 
 WARNMORE= # -g -DPNG_DEBUG=5
-CFLAGS=$(ABI) -I$(ZLIBINC) -O $(WARNMORE) -fPIC -mabi=n32
+CFLAGS=-DPNG_CONFIGURE_LIBPNG $(ABI) -I$(ZLIBINC) -O $(WARNMORE) -fPIC -mabi=n32
 LDFLAGS=$(ABI) -L. -L$(ZLIBLIB) -lpng -lz -lm
 LDSHARED=cc $(ABI) -shared -soname $(LIBSOMAJ) \
   -set_version sgi$(PNGMAJ).0
diff --git a/scripts/makefile.sgi b/scripts/makefile.sgi
index b83abc0cc99a5dcd338075181bd1ca71bf201747..180cf2b68456ca15755fee9474e60841211e7615 100644
--- a/scripts/makefile.sgi
+++ b/scripts/makefile.sgi
@@ -48,8 +48,8 @@ ABI=
 
 WARNMORE=-fullwarn
 # Note: -KPIC is the default anyhow
-#CFLAGS= $(ABI) -I$(ZLIBINC) -O $(WARNMORE) -KPIC # -g -DPNG_DEBUG=5
-CFLAGS=$(ABI) -I$(ZLIBINC) -O $(WARNMORE)
+#CFLAGS= -DPNG_CONFIGURE_LIBPNG $(ABI) -I$(ZLIBINC) -O $(WARNMORE) -KPIC # -g -DPNG_DEBUG=5
+CFLAGS=-DPNG_CONFIGURE_LIBPNG $(ABI) -I$(ZLIBINC) -O $(WARNMORE)
 LDFLAGS_A=$(ABI) -L. -L$(ZLIBLIB) -lpng14 -lz -lm
 LDFLAGS=$(ABI) -L. -L$(ZLIBLIB) -lpng -lz -lm
 LDSHARED=cc $(ABI) -shared -soname $(LIBSOMAJ) \
diff --git a/scripts/makefile.so9 b/scripts/makefile.so9
index f79afe32aa78702bf0eb5ada88da3b9c983e1ba3..45c3fa88487d9ac5cfad84052c968e4e09f2a955 100644
--- a/scripts/makefile.so9
+++ b/scripts/makefile.so9
@@ -50,8 +50,8 @@ ZLIBINC=/usr/include
 #WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 	-Wmissing-declarations -Wtraditional -Wcast-align \
 	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-#CFLAGS=-I$(ZLIBINC) -W -Wall -O3 $(WARNMORE) -g -DPNG_DEBUG=5 -DPNG_NO_MMX_CODE
-CFLAGS=-I$(ZLIBINC) -O3 -DPNG_NO_MMX_CODE
+#CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -W -Wall -O3 $(WARNMORE) -g -DPNG_DEBUG=5 -DPNG_NO_MMX_CODE
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -O3 -DPNG_NO_MMX_CODE
 LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng14 -lz -lm
 
 INCPATH=$(prefix)/include
diff --git a/scripts/makefile.solaris b/scripts/makefile.solaris
index ce21cf08fd547e4c280c4b67d3d1fbe6b0fb2f8f..a6b9b79762ece3fc80d9ed6a7d7562e616ea4f64 100644
--- a/scripts/makefile.solaris
+++ b/scripts/makefile.solaris
@@ -46,7 +46,7 @@ ZLIBINC=/usr/local/include
 WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 	-Wmissing-declarations -Wtraditional -Wcast-align \
 	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-CFLAGS=-I$(ZLIBINC) -W -Wall -O \
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -W -Wall -O \
 	# $(WARNMORE) -g -DPNG_DEBUG=5
 LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng14 -lz -lm
 
diff --git a/scripts/makefile.std b/scripts/makefile.std
index afb885ad0ff836ba0d04dddf99c785b9cd420a1c..60f7c0d8bb934e73b988a11ced26a81bf659c9e2 100644
--- a/scripts/makefile.std
+++ b/scripts/makefile.std
@@ -34,7 +34,7 @@ LN_SF=ln -sf
 RANLIB=ranlib
 RM_F=rm -f
 
-CFLAGS=-I$(ZLIBINC) -O # -g -DPNG_DEBUG=5
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -O # -g -DPNG_DEBUG=5
 LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
 
 OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
diff --git a/scripts/makefile.sunos b/scripts/makefile.sunos
index 984379c0c5243012a2383e050a5115235575a8cb..898665c566619260c1da873d4648cfe195c3d191 100644
--- a/scripts/makefile.sunos
+++ b/scripts/makefile.sunos
@@ -39,7 +39,7 @@ LN_SF=ln -f -s
 RANLIB=ranlib
 RM_F=/bin/rm -f
 
-CFLAGS=-I$(ZLIBINC) -O # $(WARNMORE) -DPNG_DEBUG=5
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -I$(ZLIBINC) -O # $(WARNMORE) -DPNG_DEBUG=5
 LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
 
 OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
diff --git a/scripts/makefile.tc3 b/scripts/makefile.tc3
index e9e49bacb1fdc515d6db02841885bbff50c2ef95..ecce8be0ebcf4449ecf8f58bd24632a7cd3c1e84 100644
--- a/scripts/makefile.tc3
+++ b/scripts/makefile.tc3
@@ -6,8 +6,8 @@
 # ----- Turbo C 3.00 (can be modified to work with earlier versions) -----
 
 MODEL=l
-CFLAGS=-O2 -Z -m$(MODEL) -I..\zlib
-#CFLAGS=-D_NO_PROTO -O2 -Z -m$(MODEL) -I..\zlib  # Turbo C older than 3.00
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -O2 -Z -m$(MODEL) -I..\zlib
+#CFLAGS=-DPNG_CONFIGURE_LIBPNG -D_NO_PROTO -O2 -Z -m$(MODEL) -I..\zlib  # Turbo C older than 3.00
 CC=tcc
 LD=tcc
 LIB=tlib
diff --git a/scripts/makefile.vcawin32 b/scripts/makefile.vcawin32
index 0b74422745052aadf1aa7cec525e626b6e46bc50..7b65a6b6afa2a0e26e58e530f3e6bf05ef77b346 100644
--- a/scripts/makefile.vcawin32
+++ b/scripts/makefile.vcawin32
@@ -15,7 +15,7 @@
 CC = cl
 LD = link
 AR = lib
-CFLAGS  = -nologo -MD -O2 -W3 -I..\zlib
+CFLAGS  = -DPNG_CONFIGURE_LIBPNG -nologo -MD -O2 -W3 -I..\zlib
 LDFLAGS = -nologo
 ARFLAGS = -nologo
 RM = del
diff --git a/scripts/makefile.vcwin32 b/scripts/makefile.vcwin32
index 5cf085e84e64535ac0356190cae2d13af142c608..38367091ff86f2b3334d14937717ce39cf5be560 100644
--- a/scripts/makefile.vcwin32
+++ b/scripts/makefile.vcwin32
@@ -15,7 +15,7 @@
 CC = cl
 LD = link
 AR = lib
-CFLAGS  = -nologo -MD -O2 -W3 -I..\zlib
+CFLAGS  = -DPNG_CONFIGURE_LIBPNG -nologo -MD -O2 -W3 -I..\zlib
 LDFLAGS = -nologo
 ARFLAGS = -nologo
 RM = del
diff --git a/scripts/makefile.watcom b/scripts/makefile.watcom
index 91742a46e53a18c0ea3ac56bbf6280b1a1907369..fee677841c3c8d54bcaea0fabf0cf2dee5abad5c 100644
--- a/scripts/makefile.watcom
+++ b/scripts/makefile.watcom
@@ -36,7 +36,7 @@ CALLING=r	# registers
 
 
 CC=wcc386
-CFLAGS=-$(CPU)$(CALLING) -fp$(CPU) -fpi87 -oneatx -mf -bt=$(OS) -i=$(ZLIBINC) -zq
+CFLAGS=-DPNG_CONFIGURE_LIBPNG -$(CPU)$(CALLING) -fp$(CPU) -fpi87 -oneatx -mf -bt=$(OS) -i=$(ZLIBINC) -zq
 LD=wcl386
 LDFLAGS=-zq
 
diff --git a/scripts/makefile.wce b/scripts/makefile.wce
index 5b023df94b9ec76735bb15b89028dd98fa9f4845..37114a3d13a509f44a933a2e7ce21285d80c9ac7 100644
--- a/scripts/makefile.wce
+++ b/scripts/makefile.wce
@@ -64,7 +64,7 @@ copy-src:
 
 compilation:
 	@echo " * Compilation of $(PACKAGE)"
-	cd $(PACKAGE) && CPPFLAGS="$(CPPFLAGS) -DPNG_BUILD_DLL -DPNG_CONSOLE_IO_SUPPORTED -DPNG_NO_MMX_CODE -D_WIN32_WCE=0x0420" CFLAGS="$(CFLAGS) -mms-bitfields -O3 -pipe -fomit-frame-pointer" LDFLAGS="$(LDFLAGS) -Wl,--enable-auto-import -Wl,-s" ./configure --prefix=/opt/wince --host=arm-mingw32ce && make
+	cd $(PACKAGE) && CPPFLAGS="$(CPPFLAGS) -DPNG_BUILD_DLL -DPNG_CONSOLE_IO_SUPPORTED -DPNG_NO_MMX_CODE -D_WIN32_WCE=0x0420" CFLAGS="$(CFLAGS) -DPNG_CONFIGURE_LIBPNG -mms-bitfields -O3 -pipe -fomit-frame-pointer" LDFLAGS="$(LDFLAGS) -Wl,--enable-auto-import -Wl,-s" ./configure --prefix=/opt/wince --host=arm-mingw32ce && make
 
 copy:
 	@echo " * Copy of binary and development files"