package/libpri: add -fPIC

Fixes:
 - https://bugs.buildroot.org/show_bug.cgi?id=11961

[Retrieved (and updated to keep line under 80 characters) from:
https://bugs.buildroot.org/show_bug.cgi?id=11961]
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

(cherry picked from commit fe9e709254c3bae8da5428f06a37900269537b64)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libpri/libpri.mk

@@ -33,7 +33,8 @@ endif
 LIBPRI_UTILS = pridump pritest rosetest testprilib
 
 define LIBPRI_BUILD_CMDS
-	$(TARGET_MAKE_ENV) $(MAKE) $(TARGET_CONFIGURE_OPTS) -C $(@D) \
+	$(TARGET_MAKE_ENV) $(MAKE1) $(TARGET_CONFIGURE_OPTS) \
+		CFLAGS="$(TARGET_CFLAGS) -fPIC" -C $(@D) \
 		$(LIBPRI_LIBS) $(LIBPRI_UTILS)
 endef