pcre: fix paths in config file

The paths are pointing to OS paths, not OpenWrt ones. Use SED line from
libpng to fix and adjust accordingly.

This may allow certain packages that use the config file to pick up pcre.

Signed-off-by: Rosen Penev <[email protected]>

package/libs/pcre/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=pcre
 PKG_VERSION:=8.44
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=@SF/$(PKG_NAME)
@@ -87,6 +87,7 @@ MAKE_FLAGS += \
 define Build/InstallDev
 	$(INSTALL_DIR) $(1)/usr/bin
 	$(INSTALL_BIN) $(PKG_INSTALL_DIR)/usr/bin/pcre-config $(1)/usr/bin/
+	$(SED) 's,^\(prefix\|exec_prefix\)=.*,\1=$(STAGING_DIR)/usr,g' $(1)/usr/bin/pcre-config
 
 	$(INSTALL_DIR) $(2)/bin
 	$(LN) $(STAGING_DIR)/usr/bin/pcre-config $(2)/bin