box2d, add pkgconfig file (fixed detection for caveexpress/cavepacker) (#5213)

dev-games/box2d/box2d-2.3.1.recipe

@@ -5,7 +5,7 @@ winner of the 2008 Independant Game Festival Grand Prize"
 HOMEPAGE="http://www.box2d.org"
 COPYRIGHT="2007-2015 Erin Catto"
 LICENSE="MIT"
-REVISION="6"
+REVISION="7"
 SOURCE_URI="https://github.com/erincatto/Box2D/archive/v$portVersion.tar.gz"
 CHECKSUM_SHA256="58ffc8475a8650aadc351345aef696937747b40501ab78d72c197c5ff5b3035c"
 SOURCE_DIR="box2d-$portVersion"
@@ -15,7 +15,7 @@ ARCHITECTURES="x86_gcc2 !x86 x86_64"
 SECONDARY_ARCHITECTURES="x86"
 
 PROVIDES="
-	box2d$secondaryArchSuffix = $portVersion compat >= 2.0
+	box2d$secondaryArchSuffix = $portVersion
 	lib:libBox2D$secondaryArchSuffix = 2.3.0
 	"
 REQUIRES="
@@ -63,5 +63,22 @@ INSTALL()
 	make install
 
 	prepareInstalledDevelLib libBox2D
-	packageEntries devel $developDir $libDir/cmake
+
+	mkdir -p $developLibDir/pkgconfig
+	cat > $developLibDir/pkgconfig/box2d.pc << EOF
+prefix=${prefix}
+exec_prefix=${prefix}
+libdir=${libDir}
+includedir=${includeDir}
+
+Name: box2d
+Description: $SUMMARY
+Version: $portVersion
+Libs: -L${developLibDir} -lBox2D
+Cflags: -I${includeDir}
+EOF
+
+	packageEntries devel \
+		$developDir \
+		$libDir/cmake
 }