groff: Fix math.h inclusion from system headers issue

groff has system headers overrides in its sourcecode which it
generates as fallbacks but in some cases when a system header includes
math.h via include <> directive it lands in the override header and
causes compile issues, seen with clang+libc++, this patch makes sure
that right defines are available before including it

(From OE-Core rev: e9beba2a33b46d31bfdd926211d22ebf2abb6c90)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/groff/groff_1.22.4.bb

@@ -11,6 +11,7 @@ SRC_URI = "${GNU_MIRROR}/groff/groff-${PV}.tar.gz \
 	file://0001-replace-perl-w-with-use-warnings.patch \
 	file://groff-not-search-fonts-on-build-host.patch \
 	file://0001-support-musl.patch \
+	file://0001-Include-config.h.patch \
 "
 
 SRC_URI[md5sum] = "08fb04335e2f5e73f23ea4c3adbf0c5f"