fvwm: Disable int-conversion and implicit-int warnings as errors

Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-graphics/fvwm/fvwm_2.6.9.bb

@@ -75,6 +75,8 @@ EXTRA_OECONF = " \
 EXTRA_OEMAKE = " \
     V=1 \
 "
+# clang treats them as errors by default now starting with 15.0+
+CFLAGS += "-Wno-error=int-conversion -Wno-error=implicit-int"
 
 do_install:append() {
     install -d -m 0755 ${D}/${sysconfdir}/xdg/fvwm