It seems like gcc-drivven shared library building on OpenUnix 8 requires

-shared rather than -G.

Configure

@@ -433,7 +433,7 @@ my %table=(
 "unixware-7","cc:-O -DFILIO_H -Kalloca::-Kthread::-lsocket -lnsl:BN_LLONG MD2_CHAR RC4_INDEX ${x86_gcc_des}:${x86_elf_asm}:dlfcn:svr5-shared:-Kpic::.so.\$(SHLIB_MAJOR).\$(SHLIB_MINOR)",
 "unixware-7-gcc","gcc:-DL_ENDIAN -DFILIO_H -O3 -fomit-frame-pointer -m486 -Wall::-D_REENTRANT::-lsocket -lnsl:BN_LLONG ${x86_gcc_des} ${x86_gcc_opts}:${x86_elf_asm}:dlfcn:gnu-shared:-fPIC::.so.\$(SHLIB_MAJOR).\$(SHLIB_MINOR)",
 "OpenUNIX-8","cc:-O -DFILIO_H -Kalloca::-Kthread::-lsocket -lnsl:BN_LLONG MD2_CHAR RC4_INDEX ${x86_gcc_des}:${x86_elf_asm}:dlfcn:svr5-shared:-Kpic::.so.\$(SHLIB_MAJOR).\$(SHLIB_MINOR)",
-"OpenUNIX-8-gcc","gcc:-O -DFILIO_H -fomit-frame-pointer::-pthread::-lsocket -lnsl:BN_LLONG MD2_CHAR RC4_INDEX ${x86_gcc_des}:${x86_elf_asm}:dlfcn:gnu-shared:-fPIC::.so.\$(SHLIB_MAJOR).\$(SHLIB_MINOR)",
+"OpenUNIX-8-gcc","gcc:-O -DFILIO_H -fomit-frame-pointer::-pthread::-lsocket -lnsl:BN_LLONG MD2_CHAR RC4_INDEX ${x86_gcc_des}:${x86_elf_asm}:dlfcn:svr5-shared:-fPIC::.so.\$(SHLIB_MAJOR).\$(SHLIB_MINOR)",
 "sco3-gcc",  "gcc:-O3 -fomit-frame-pointer -Dssize_t=int -DNO_SYS_UN_H::(unknown)::-lsocket:BN_LLONG ${x86_gcc_des} ${x86_gcc_opts}:::", # the SCO assembler doesn't seem to like our assembler files ...
 # SCO 5 - Ben Laurie <ben@algroup.co.uk> says the -O breaks the SCO cc.
 "sco5-cc",  "cc:-belf::(unknown)::-lsocket -lnsl:${x86_gcc_des} ${x86_gcc_opts}:${x86_elf_asm}:dlfcn:svr3-shared:-Kpic::.so.\$(SHLIB_MAJOR).\$(SHLIB_MINOR)",

Makefile.shared

@@ -456,12 +456,14 @@ link_o.svr3:
 		$(DO_GNU_SO); \
 	else \
 		$(CALC_VERSIONS); \
+		SHARE_FLAG='-G'; \
+		(${CC} -v 2>&1 | grep gcc) > /dev/null && SHARE_FLAGS='-shared'; \
 		SHLIB=lib$(LIBNAME).so; \
 		SHLIB_SUFFIX=; \
 		LIBDEPS="$(LIBDEPS) -lc"; \
 		ALLSYMSFLAGS='-z allextract'; \
 		NOALLSYMSFLAGS=''; \
-		SHAREDFLAGS="-G -h $$SHLIB$$SHLIB_SOVER$$SHLIB_SUFFIX"; \
+		SHAREDFLAGS="$${SHARE_FLAG} -h $$SHLIB$$SHLIB_SOVER$$SHLIB_SUFFIX"; \
 		SHAREDCMD='$(CC)'; \
 	fi; \
 	$(LINK_SO_O)
@@ -470,12 +472,14 @@ link_a.svr3:
 		$(DO_GNU_SO); \
 	else \
 		$(CALC_VERSIONS); \
+		SHARE_FLAG='-G'; \
+		(${CC} -v 2>&1 | grep gcc) > /dev/null && SHARE_FLAGS='-shared'; \
 		SHLIB=lib$(LIBNAME).so; \
 		SHLIB_SUFFIX=; \
 		LIBDEPS="$(LIBDEPS) -lc"; \
 		ALLSYMSFLAGS='-z allextract'; \
 		NOALLSYMSFLAGS=''; \
-		SHAREDFLAGS="-G -h $$SHLIB$$SHLIB_SOVER$$SHLIB_SUFFIX"; \
+		SHAREDFLAGS="$${SHARE_FLAG} -h $$SHLIB$$SHLIB_SOVER$$SHLIB_SUFFIX"; \
 		SHAREDCMD='$(CC)'; \
 	fi; \
 	$(LINK_SO_A_UNPACKED)