[PATCH] configure: force enable-sanitizers together with enable-fuzzing

[Li Qiang <liq3ea@163.com>]

If we execute configure with --enable-fuzzing but without
--enable-sanitizers, we will have a lot of 'undefined reference'
build error such as following:

clang-10  -o subprojects/libvhost-user/link-test subprojects/libvhost-user/link-test.p/link-test.c.o -Wl,--as-needed -Wl,--no-undefined -pie -Wl,--whole-archive -Wl,--start-group subprojects/libvhost-user/libvhost-user.a -Wl,--end-group -Wl,--no-whole-archive -Wl,--warn-common -Wl,-z,relro -Wl,-z,now -m64 -fstack-protector-strong -pthread
/usr/bin/ld: subprojects/libvhost-user/link-test.p/link-test.c.o: in function `main':
/home/test/qemu/build/../subprojects/libvhost-user/link-test.c:34: undefined reference to `__sancov_lowest_stack'
/usr/bin/ld: /home/test/qemu/build/../subprojects/libvhost-user/link-test.c:(.text.main[main]+0x55): undefined reference to `__sancov_lowest_stack'
/usr/bin/ld: /home/test/qemu/build/../subprojects/libvhost-user/link-test.c:41: undefined reference to `__sanitizer_cov_trace_const_cmp4'
/usr/bin/ld: subprojects/libvhost-user/link-test.p/link-test.c.o: in function `sancov.module_ctor_8bit_counters':
link-test.c:(.text.sancov.module_ctor_8bit_counters[sancov.module_ctor_8bit_counters]+0x16): undefined reference to `__sanitizer_cov_8bit_counters_init'
/usr/bin/ld: link-test.c:(.text.sancov.module_ctor_8bit_counters[sancov.module_ctor_8bit_counters]+0x2f): undefined reference to `__sanitizer_cov_pcs_init'
/usr/bin/ld: subprojects/libvhost-user/libvhost-user.a(libvhost-user.c.o): in function `vu_gpa_to_va':
/home/test/qemu/build/../subprojects/libvhost-user/libvhost-user.c:182: undefined reference to `__sanitizer_cov_trace_const_cmp8'
/usr/bin/ld: /home/test/qemu/build/../subprojects/libvhost-user/libvhost-user.c:187: undefined reference to `__sanitizer_cov_trace_cmp4'
/usr/bin/ld: /home/test/qemu/build/../subprojects/libvhost-user/libvhost-user.c:190: undefined reference to `__sanitizer_cov_trace_cmp8'
/usr/bin/ld: /home/test/qemu/build/../subprojects/libvhost-user/libvhost-user.c:190: undefined reference to `__sanitizer_cov_trace_cmp8'
/usr/bin/ld: /home/test/qemu/build/../subprojects/libvhost-user/libvhost-user.c:191: undefined reference to `__sanitizer_cov_trace_cmp8'

Let's avoid this error by enforcing fuzzing and sanitizers together.

Signed-off-by: Li Qiang <liq3ea@163.com>
---
 configure | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/configure b/configure
index a34f91171d..9f00a1d887 100755
--- a/configure
+++ b/configure
@@ -6083,6 +6083,9 @@ if test "$have_mlockall" = "yes" ; then
   echo "HAVE_MLOCKALL=y" >> $config_host_mak
 fi
 if test "$fuzzing" = "yes" ; then
+  if test "$sanitizers" = "no"; then
+    error_exit "enable-fuzzing also needs enable-sanitizers"
+  fi
   # If LIB_FUZZING_ENGINE is set, assume we are running on OSS-Fuzz, and the
   # needed CFLAGS have already been provided
   if test -z "${LIB_FUZZING_ENGINE+xxx}" ; then
-- 
2.25.1