[PATCH BlueZ v1 1/2] build: Enable -Wstringop-overflow and -D_FORTIFY_SOURCE=3

[Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx>]

From: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>

This enables -Wstringop-overflow compiler warnings:

  'Warn for calls to string manipulation functions such as "memcpy" and
  "strcpy" that are determined to overflow the destination buffer.'

Along with -D_FORTIFY_SOURCE=3 so the errors like the following can be
captured:

In function ‘read’,
    inlined from ‘serial_read_callback’ at emulator/serial.c:90:8:
/usr/include/bits/unistd.h:32:10: error: ‘__read_alias’ specified size between 18446744073709490177 and 18446744073709551615 exceeds maximum object size 9223372036854775807 [-Werror=stringop-overflow=]
   32 |   return __glibc_fortify (read, __nbytes, sizeof (char),
      |          ^~~~~~~~~~~~~~~
---
 acinclude.m4 | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/acinclude.m4 b/acinclude.m4
index 4b73a5bfc38f..7f8e28d0bdaf 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -61,9 +61,11 @@ AC_DEFUN([COMPILER_FLAGS], [
 		with_cflags="$with_cflags -Wcast-align"
 		with_cflags="$with_cflags -Wswitch-enum"
 		with_cflags="$with_cflags -Wformat -Wformat-security"
+		with_cflags="$with_cflags -Wstringop-overflow"
 		with_cflags="$with_cflags -DG_DISABLE_DEPRECATED"
 		with_cflags="$with_cflags -DGLIB_VERSION_MIN_REQUIRED=GLIB_VERSION_2_28"
 		with_cflags="$with_cflags -DGLIB_VERSION_MAX_ALLOWED=GLIB_VERSION_2_32"
+		with_cflags="$with_cflags -D_FORTIFY_SOURCE=3"
 	fi
 	AC_SUBST([WARNING_CFLAGS], $with_cflags)
 ])
-- 
2.48.1