uninstalled.pc: add support for non libtool build systems

Currently the .la path is provided which requires to use libtool as
mentioned in the GStreamer manual section-helloworld-compilerun.html.
It is fine as long as the application is built using libtool.

So currently it is not possible to compile a GStreamer application
within gst-uninstalled with CMake or other build system different
than autotools.

This patch allows to do the following in gst-uninstalled env:
gcc test.c -o test $(pkg-config --cflags --libs gstreamer-1.0 \
    gstreamer-video-1.0)
Previously it required to prepend libtool --mode=link

https://bugzilla.gnome.org/show_bug.cgi?id=720778

pkgconfig/gstreamer-allocators-uninstalled.pc.in

@@ -1,7 +1,7 @@
 # the standard variables don't make sense for an uninstalled copy
 prefix=
 exec_prefix=
-libdir=
+libdir=@abs_top_builddir@/gst-libs/gst/allocators/.libs
 # includedir is builddir because it is used to find gstconfig.h in places
 includedir=@abs_top_builddir@/gst-libs
 girdir=@abs_top_builddir@/gst-libs/gst/allocators
@@ -11,6 +11,6 @@ Name: GStreamer Allocators Library, Uninstalled
 Description: Allocators implementation, uninstalled
 Version: @VERSION@
 Requires: gstreamer-@GST_API_VERSION@
-Libs: @abs_top_builddir@/gst-libs/gst/allocators/libgstallocators-@GST_API_VERSION@.la
+Libs: -L${libdir} -lgstallocators-@GST_API_VERSION@
 Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs
 

pkgconfig/gstreamer-app-uninstalled.pc.in

@@ -1,7 +1,7 @@
 # the standard variables don't make sense for an uninstalled copy
 prefix=
 exec_prefix=
-libdir=
+libdir=@abs_top_builddir@/gst-libs/gst/app/.libs
 # includedir is builddir because it is used to find gstconfig.h in places
 includedir=@abs_top_builddir@/gst-libs
 girdir=@abs_top_builddir@/gst-libs/gst/app
@@ -11,6 +11,6 @@ Name: GStreamer Application Library, Uninstalled
 Description: Helper functions and base classes for application integration, uninstalled
 Version: @VERSION@
 Requires: gstreamer-@GST_API_VERSION@ gstreamer-base-@GST_API_VERSION@
-Libs: @abs_top_builddir@/gst-libs/gst/app/libgstapp-@GST_API_VERSION@.la
+Libs: -L${libdir} -lgstapp-@GST_API_VERSION@
 Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs
 

pkgconfig/gstreamer-audio-uninstalled.pc.in

@@ -1,7 +1,7 @@
 # the standard variables don't make sense for an uninstalled copy
 prefix=
 exec_prefix=
-libdir=
+libdir=@abs_top_builddir@/gst-libs/gst/audio/.libs
 # includedir is builddir because it is used to find gstconfig.h in places
 includedir=@abs_top_builddir@/gst-libs
 girdir=@abs_top_builddir@/gst-libs/gst/audio
@@ -11,6 +11,6 @@ Name: GStreamer Audio Library, Uninstalled
 Description: Audio helper functions and base classes, uninstalled
 Version: @VERSION@
 Requires: gstreamer-@GST_API_VERSION@ gstreamer-base-@GST_API_VERSION@
-Libs: @abs_top_builddir@/gst-libs/gst/audio/libgstaudio-@GST_API_VERSION@.la
+Libs: -L${libdir} -lgstaudio-@GST_API_VERSION@
 Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs
 

pkgconfig/gstreamer-fft-uninstalled.pc.in

@@ -1,7 +1,7 @@
 # the standard variables don't make sense for an uninstalled copy
 prefix=
 exec_prefix=
-libdir=
+libdir=@abs_top_builddir@/gst-libs/gst/fft/.libs
 # includedir is builddir because it is used to find gstconfig.h in places
 includedir=@abs_top_builddir@/gst-libs
 girdir=@abs_top_builddir@/gst-libs/gst/fft
@@ -11,6 +11,6 @@ Name: GStreamer FFT Library, Uninstalled
 Description: FFT implementation, uninstalled
 Version: @VERSION@
 Requires: gstreamer-@GST_API_VERSION@
-Libs: @abs_top_builddir@/gst-libs/gst/fft/libgstfft-@GST_API_VERSION@.la @LIBM@
+Libs: -L${libdir} -lgstfft-@GST_API_VERSION@ @LIBM@
 Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs
 

pkgconfig/gstreamer-pbutils-uninstalled.pc.in

@@ -1,7 +1,7 @@
 # the standard variables don't make sense for an uninstalled copy
 prefix=
 exec_prefix=
-libdir=
+libdir=@abs_top_builddir@/gst-libs/gst/pbutils/.libs
 # includedir is builddir because it is used to find gstconfig.h in places
 includedir=@abs_top_builddir@/gst-libs
 girdir=@abs_top_builddir@/gst-libs/gst/pbutils
@@ -11,6 +11,6 @@ Name: GStreamer Base Utils Library, Uninstalled
 Description: General utility functions, uninstalled
 Version: @VERSION@
 Requires: gstreamer-@GST_API_VERSION@
-Libs: @abs_top_builddir@/gst-libs/gst/pbutils/libgstpbutils-@GST_API_VERSION@.la
+Libs: -L${libdir} -lgstpbutils-@GST_API_VERSION@
 Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs
 

pkgconfig/gstreamer-plugins-base-uninstalled.pc.in

@@ -10,7 +10,7 @@ Name: GStreamer Base Plugins Libraries, Uninstalled
 Description: Streaming media framework, base plugins libraries, uninstalled
 Version: @VERSION@
 Requires: gstreamer-@GST_API_VERSION@
-Libs: -L@abs_top_builddir@/gst-libs/gst/allocators -L@abs_top_builddir@/gst-libs/gst/app -L@abs_top_builddir@/gst-libs/gst/audio -L@abs_top_builddir@/gst-libs/gst/fft -L@abs_top_builddir@/gst-libs/gst/pbutils -L@abs_top_builddir@/gst-libs/gst/riff -L@abs_top_builddir@/gst-libs/gst/rtp -L@abs_top_builddir@/gst-libs/gst/rtsp -L@abs_top_builddir@/gst-libs/gst/sdp -L@abs_top_builddir@/gst-libs/gst/tag -L@abs_top_builddir@/gst-libs/gst/video
+Libs: -L@abs_top_builddir@/gst-libs/gst/allocators/.libs -L@abs_top_builddir@/gst-libs/gst/app/.libs -L@abs_top_builddir@/gst-libs/gst/audio/.libs -L@abs_top_builddir@/gst-libs/gst/fft/.libs -L@abs_top_builddir@/gst-libs/gst/pbutils/.libs -L@abs_top_builddir@/gst-libs/gst/riff/.libs -L@abs_top_builddir@/gst-libs/gst/rtp/.libs -L@abs_top_builddir@/gst-libs/gst/rtsp/.libs -L@abs_top_builddir@/gst-libs/gst/sdp/.libs -L@abs_top_builddir@/gst-libs/gst/tag/.libs -L@abs_top_builddir@/gst-libs/gst/video/.libs
 Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs
 
 libraries=allocators app audio fft pbutils riff rtp rtsp sdp tag video

pkgconfig/gstreamer-riff-uninstalled.pc.in

@@ -1,7 +1,7 @@
 # the standard variables don't make sense for an uninstalled copy
 prefix=
 exec_prefix=
-libdir=
+libdir=@abs_top_builddir@/gst-libs/gst/riff/.libs
 # includedir is builddir because it is used to find gstconfig.h in places
 includedir=@abs_top_builddir@/gst-libs
 girdir=@abs_top_builddir@/gst-libs/gst/riff
@@ -11,6 +11,6 @@ Name: GStreamer RIFF Library, Uninstalled
 Description: RIFF helper functions, uninstalled
 Version: @VERSION@
 Requires: gstreamer-@GST_API_VERSION@
-Libs: @abs_top_builddir@/gst-libs/gst/riff/libgstriff-@GST_API_VERSION@.la
+Libs: -L${libdir} -lgstriff-@GST_API_VERSION@
 Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs
 

pkgconfig/gstreamer-rtp-uninstalled.pc.in

@@ -1,7 +1,7 @@
 # the standard variables don't make sense for an uninstalled copy
 prefix=
 exec_prefix=
-libdir=
+libdir=@abs_top_builddir@/gst-libs/gst/rtp/.libs
 # includedir is builddir because it is used to find gstconfig.h in places
 includedir=@abs_top_builddir@/gst-libs
 girdir=@abs_top_builddir@/gst-libs/gst/rtp
@@ -11,6 +11,6 @@ Name: GStreamer RTP Library, Uninstalled
 Description: RTP base classes and helper functions, uninstalled
 Version: @VERSION@
 Requires: gstreamer-@GST_API_VERSION@ gstreamer-base-@GST_API_VERSION@
-Libs: @abs_top_builddir@/gst-libs/gst/rtp/libgstrtp-@GST_API_VERSION@.la
+Libs: -L${libdir} -lgstrtp-@GST_API_VERSION@
 Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs
 

pkgconfig/gstreamer-rtsp-uninstalled.pc.in

@@ -1,7 +1,7 @@
 # the standard variables don't make sense for an uninstalled copy
 prefix=
 exec_prefix=
-libdir=
+libdir=@abs_top_builddir@/gst-libs/gst/rtsp/.libs
 # includedir is builddir because it is used to find gstconfig.h in places
 includedir=@abs_top_builddir@/gst-libs
 girdir=@abs_top_builddir@/gst-libs/gst/rtsp
@@ -11,6 +11,6 @@ Name: GStreamer RTSP Library, Uninstalled
 Description: RTSP base classes and helper functions, uninstalled
 Version: @VERSION@
 Requires: gstreamer-@GST_API_VERSION@ gstreamer-sdp-@GST_API_VERSION@ gio-2.0
-Libs: @abs_top_builddir@/gst-libs/gst/rtsp/libgstrtsp-@GST_API_VERSION@.la
+Libs: -L${libdir} -lgstrtsp-@GST_API_VERSION@
 Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs
 

pkgconfig/gstreamer-sdp-uninstalled.pc.in

@@ -1,7 +1,7 @@
 # the standard variables don't make sense for an uninstalled copy
 prefix=
 exec_prefix=
-libdir=
+libdir=@abs_top_builddir@/gst-libs/gst/sdp/.libs
 # includedir is builddir because it is used to find gstconfig.h in places
 includedir=@abs_top_builddir@/gst-libs
 girdir=@abs_top_builddir@/gst-libs/gst/sdp
@@ -12,6 +12,6 @@ Description: SDP helper functions, uninstalled
 Version: @VERSION@
 Requires: glib-2.0
 Requires.private: gio-2.0
-Libs: @abs_top_builddir@/gst-libs/gst/sdp/libgstsdp-@GST_API_VERSION@.la
+Libs: -L${libdir} -lgstsdp-@GST_API_VERSION@
 Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs
 

pkgconfig/gstreamer-tag-uninstalled.pc.in

@@ -1,7 +1,7 @@
 # the standard variables don't make sense for an uninstalled copy
 prefix=
 exec_prefix=
-libdir=
+libdir=@abs_top_builddir@/gst-libs/gst/tag/.libs
 # includedir is builddir because it is used to find gstconfig.h in places
 includedir=@abs_top_builddir@/gst-libs
 girdir=@abs_top_builddir@/gst-libs/gst/tag
@@ -11,6 +11,6 @@ Name: GStreamer Tag Library, Uninstalled
 Description: Tag base classes and helper functions, uninstalled
 Version: @VERSION@
 Requires: gstreamer-@GST_API_VERSION@
-Libs: @abs_top_builddir@/gst-libs/gst/tag/libgsttag-@GST_API_VERSION@.la
+Libs: -L${libdir} -lgsttag-@GST_API_VERSION@
 Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs
 

pkgconfig/gstreamer-video-uninstalled.pc.in

@@ -1,7 +1,7 @@
 # the standard variables don't make sense for an uninstalled copy
 prefix=
 exec_prefix=
-libdir=
+libdir=@abs_top_builddir@/gst-libs/gst/video/.libs
 # includedir is builddir because it is used to find gstconfig.h in places
 includedir=@abs_top_builddir@/gst-libs
 girdir=@abs_top_builddir@/gst-libs/gst/video
@@ -11,6 +11,6 @@ Name: GStreamer Video Library, Uninstalled
 Description: Video base classes and helper functions, uninstalled
 Version: @VERSION@
 Requires: gstreamer-@GST_API_VERSION@ gstreamer-base-@GST_API_VERSION@
-Libs: @abs_top_builddir@/gst-libs/gst/video/libgstvideo-@GST_API_VERSION@.la
+Libs: -L${libdir} -lgstvideo-@GST_API_VERSION@
 Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs