build: Generate the map file from the configured ABI

Some linkers require the map file definitions to contain only symbols
that are present on the linked object, either in the map file or in the
sym file we generate from the map file.

This is preparatory work to be able to conditionally include symbols
in the man and sym files depending on the ABI definitions.

.gitignore

@@ -11,6 +11,7 @@ ChangeLog
 *.gcda
 *.gcno
 *.sym
+*.map
 .dirstamp
 .deps/
 .libs/

src/Makefile.am

@@ -28,7 +28,7 @@ libbsd_la_included_sources = \
 
 CLEANFILES =
 EXTRA_DIST = \
-	libbsd.map \
+	libbsd.map.in \
 	libbsd.pc.in \
 	libbsd-ctor.pc.in \
 	libbsd-overlay.pc.in \
@@ -53,6 +53,7 @@ endif
 EXTRA_libbsd_la_DEPENDENCIES = \
 	$(libbsd_la_included_sources) \
 	libbsd.map \
+	libbsd.map.in \
 	# EOL
 libbsd_la_LIBADD = \
 	$(MD5_LIBS) \
@@ -64,7 +65,7 @@ libbsd_la_LDFLAGS = \
 	# EOL
 if HAVE_LINKER_VERSION_SCRIPT
 libbsd_la_LDFLAGS += \
-	-Wl,--version-script=$(srcdir)/libbsd.map \
+	-Wl,--version-script=libbsd.map \
 	# EOL
 else
 libbsd_la_LDFLAGS += \
@@ -194,12 +195,18 @@ endif
 
 DISTCLEANFILES = \
 	libbsd.sym \
+	libbsd.map \
 	# EOL
 
 libbsd_ctor_a_SOURCES = \
 	setproctitle_ctor.c \
 	# EOL
 
+# Generate the library map file with the pre-processor to selectively include
+# symbols depending on the host system, otherwise some linkers might fail.
+libbsd.map: libbsd.map.in
+	$(CPP) $(AM_CPPFLAGS) $(CPPFLAGS) -P - <$(srcdir)/libbsd.map.in >$@
+
 # Generate a simple libtool symbol export list to be used as a fallback if
 # there is no version script support.
 libbsd.sym: libbsd.map

src/libbsd.map.in

@@ -1,3 +1,5 @@
+#include "config.h"
+
 LIBBSD_0.0 {
   global:
     arc4random;