Add hooks to build libc with symbol versioning. This is

disabled by default; add SYMVER_ENABLED=true to /etc/make.conf
to enable it.  libc should get a version bump before this is
enabled by default.

Reviewed by:	davidxu

1 files changed, 14 insertions, 0 deletions

diff --git a/lib/libc/Makefile b/lib/libc/Makefile
index aea5031..b0780a3 100644
--- a/lib/libc/Makefile
+++ b/lib/libc/Makefile
@@ -18,6 +18,8 @@ CFLAGS+=-I${.CURDIR}/${MACHINE_ARCH}
 CLEANFILES+=tags
 INSTALL_PIC_ARCHIVE=
 PRECIOUSLIB=
+VERSION_DEF=Versions.def
+VERSION_MAP=Version.map
 
 # Define (empty) variables so that make doesn't give substitution
 # errors if the included makefiles don't change these:
@@ -94,7 +96,19 @@ libkern.${MACHINE_ARCH}:: ${KMSRCS}
 	cp -p ${.ALLSRC} ${DESTDIR}/sys/libkern/${MACHINE_ARCH}
 .endif
 
+${VERSION_MAP}: ${SYM_MAPS}
+	awk -v vfile=${.CURDIR}/Versions.def -f ${.CURDIR}/version_gen.awk \
+	    ${SYM_MAPS} > ${.TARGET}
+
+        
 .include <bsd.lib.mk>
 
 # Disable warnings in contributed sources.
 CWARNFLAGS:=	${.IMPSRC:Ngdtoa_*.c:C/^.+$/${CWARNFLAGS}/}
+
+.if defined(SYMVER_ENABLED)
+CFLAGS+= -DSYMBOL_VERSIONING
+LDFLAGS= -Wl,--version-script=${.OBJDIR}/${VERSION_MAP}
+
+${SHLIB_NAME}: ${VERSION_MAP}
+.endif