Compile dynamic library by default

Summary:
Per request, some users need to use dynamic rocksdb library instead of static one.

However currently the dynamic libraries have to be manually compiled by default, which is inconvenient. I made dymamic libraries to be compiled by default.

Test Plan: make clean; make; make clean;

Reviewers: haobo, sdong, dhruba, igor

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15117

Makefile

@@ -127,12 +127,12 @@ $(SHARED2): $(SHARED3)
 	ln -fs $(SHARED3) $(SHARED2)
 endif
 
-$(SHARED3):
-	$(CXX) $(PLATFORM_SHARED_LDFLAGS)$(SHARED2) $(CXXFLAGS) $(COVERAGEFLAGS) $(PLATFORM_SHARED_CFLAGS) $(SOURCES) -o $@ $(LDFLAGS)
+$(SHARED3): $(LIBOBJECTS)
+	$(CXX) $(PLATFORM_SHARED_LDFLAGS)$(SHARED2) $(CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) $(LDFLAGS) $(SOURCES)-o $@
 
 endif  # PLATFORM_SHARED_EXT
 
-all: $(LIBRARY) $(PROGRAMS)
+all: $(LIBRARY) $(PROGRAMS) $(SHARED)
 
 .PHONY: blackbox_crash_test check clean coverage crash_test ldb_tests \
 	release tags valgrind_check whitebox_crash_test

build_tools/build_detect_platform

@@ -81,9 +81,9 @@ PLATFORM_CCFLAGS=
 PLATFORM_CXXFLAGS="$PLATFORM_CXXFLAGS ${CXXFLAGS}"
 PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS"
 PLATFORM_SHARED_EXT="so"
-PLATFORM_SHARED_LDFLAGS="${EXEC_LDFLAGS_SHARED} -shared -Wl,-soname -Wl,"
+PLATFORM_SHARED_LDFLAGS="-shared -Wl,-soname -Wl,"
 PLATFORM_SHARED_CFLAGS="-fPIC"
-PLATFORM_SHARED_VERSIONED=true
+PLATFORM_SHARED_VERSIONED=false
 
 # generic port files (working on all platform by #ifdef) go directly in /port
 GENERIC_PORT_FILES=`find $ROCKSDB_ROOT/port -name '*.cc' | tr "\n" " "`

build_tools/fbcode.gcc481.sh

@@ -60,7 +60,7 @@ AR=$TOOLCHAIN_EXECUTABLES/binutils/binutils-2.21.1/da39a3e/bin/ar
 RANLIB=$TOOLCHAIN_EXECUTABLES/binutils/binutils-2.21.1/da39a3e/bin/ranlib
 
 CFLAGS="-B$TOOLCHAIN_EXECUTABLES/binutils/binutils-2.21.1/da39a3e/bin/gold -m64 -mtune=generic"
-CFLAGS+=" -nostdlib $LIBGCC_INCLUDE $GLIBC_INCLUDE"
+CFLAGS+=" $LIBGCC_INCLUDE $GLIBC_INCLUDE"
 CFLAGS+=" -DROCKSDB_PLATFORM_POSIX -DROCKSDB_ATOMIC_PRESENT -DROCKSDB_FALLOCATE_PRESENT"
 CFLAGS+=" -DSNAPPY -DGFLAGS -DZLIB -DBZIP2"