perl: Provide correct CFLAGS through perlmod.mk

In case threading is enabled, perl is compiled with -D_REENTRANT
and -D_GNU_SOURCE, which, apart from other things, enables usage
of off64_t. As we override module CFLAGS manually, we'll have to
pass that flags as well.

Signed-off-by: Marcel Denia <naoir@gmx.net>

lang/perl/perlmod.mk

@@ -9,6 +9,11 @@ ifneq ($(CONFIG_USE_EGLIBC),)
 endif
 PERL_CMD:=$(STAGING_DIR_HOST)/usr/bin/perl5.20.0
 
+MOD_CFLAGS_PERL:=$(TARGET_CFLAGS) $(TARGET_CPPFLAGS)
+ifdef CONFIG_PERL_THREADS
+	MOD_CFLAGS_PERL+= -D_REENTRANT -D_GNU_SOURCE
+endif
+
 # Module install prefix
 PERL_SITELIB:=/usr/lib/perl5/5.20
 PERL_TESTSDIR:=/usr/share/perl/perl-tests
@@ -54,7 +59,7 @@ define perlmod/Configure
 		$(1) \
 		AR=ar \
 		CC=$(GNU_TARGET_NAME)-gcc \
-		CCFLAGS="$(TARGET_CFLAGS) $(TARGET_CPPFLAGS)" \
+		CCFLAGS="$(MOD_CFLAGS_PERL)" \
 		CCCDLFLAGS=-fPIC \
 		CCDLFLAGS=-Wl,-E \
 		DLEXT=so \