package/fstrcmp: fix musl static build

Fix the following musl static build failure raised because host libtool
is not patched to manage "-static" as "-all-static".

/home/buildroot/autobuild/instance-2/output-1/host/bin/libtool --mode=link --tag=CC /home/buildroot/autobuild/instance-2/output-1/host/bin/arm-buildroot-linux-musleabihf-gcc -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -Os -g0  -static -Wall -Wextra -Wshadow -o bin/test_user \
	test_user/main.lo lib/libfstrcmp.la -static
chmod a+rx bin/test_prelude
libtool: link: /home/buildroot/autobuild/instance-2/output-1/host/bin/arm-buildroot-linux-musleabihf-gcc -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -g0 -Wall -Wextra -Wshadow -o bin/test_user test_user/main.o  lib/.libs/libfstrcmp.a
libtool: link: /home/buildroot/autobuild/instance-2/output-1/host/bin/arm-buildroot-linux-musleabihf-gcc -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -g0 -Wall -Wextra -Wshadow -o bin/fstrcmp fstrcmp/main.o  lib/.libs/libfstrcmp.a
/home/buildroot/autobuild/instance-2/output-1/host/lib/gcc/arm-buildroot-linux-musleabihf/10.3.0/../../../../arm-buildroot-linux-musleabihf/bin/ld: /home/buildroot/autobuild/instance-2/output-1/host/lib/gcc/arm-buildroot-linux-musleabihf/10.3.0/libgcc.a(_dvmd_lnx.o): in function `__aeabi_ldiv0':
/home/buildroot/autobuild/instance-2/output-1/build/host-gcc-final-10.3.0/build/arm-buildroot-linux-musleabihf/libgcc/../../../libgcc/config/arm/lib1funcs.S:1499: undefined reference to `raise'

Fixes:
 - http://autobuild.buildroot.org/results/ffbee12f13e3d6c180d8891a428c6c490163083d

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 094c76a2bcd301e4aa1e27c9694314079440ce5b)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/fstrcmp/fstrcmp.mk

@@ -15,6 +15,12 @@ FSTRCMP_CONF_ENV = LIBTOOL="$(HOST_DIR)/bin/libtool"
 
 FSTRCMP_MAKE_OPTS = all-bin libdir/pkgconfig/fstrcmp.pc
 
+# fstrcmp does not carry and use the usual ltmain.sh wrappers, so it does not
+# inherit from our libtool patches to make -static behave like -all-static.
+ifeq ($(BR2_STATIC_LIBS),y)
+FSTRCMP_MAKE_OPTS += LDFLAGS="$(TARGET_LDFLAGS) -all-static"
+endif
+
 # We need to install the package files ourselves due to upstream trying
 # to install a .lai file which is missing because of rpath removal
 define FSTRCMP_INSTALL_STAGING_CMDS