libgd: Switch to CMake

Size reduced from 92878 to 91675 bytes.

CMake added CXX files. Removed those.

Removed ceill patch. ceill is not used anymore.

Removed pkgconfig patch. CMake uses a different file, which does not have
this problem.

Further size reduction to 87938 with LTO.

Removed InstallDev. CMAKE_INSTALL takes care of that.

Added WebP support.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

libs/libgd/patches/100-no-cxx.patch

@@ -0,0 +1,26 @@
+--- a/src/CMakeLists.txt
++++ b/src/CMakeLists.txt
+@@ -23,8 +23,6 @@ SET (LIBGD_SRC_FILES
+ 	gd_io_dp.c
+ 	gd_io_file.c
+ 	gd_io_ss.c
+-	gd_io_stream.cxx
+-	gd_io_stream.h
+ 	gd_jpeg.c
+ 	gd_matrix.c
+ 	gd_nnquant.c
+@@ -60,8 +58,6 @@ SET (LIBGD_SRC_FILES
+ 	gdhelpers.c
+ 	gdhelpers.h
+ 	gdkanji.c
+-	gdpp.cxx
+-	gdpp.h
+ 	gdtables.c
+ 	gdxpm.c
+ 	jisx0208.h
+@@ -175,5 +171,4 @@ install(FILES
+ 	gdfonts.h
+ 	gdfontt.h
+ 	gdfx.h
+-	gdpp.h
+ 	DESTINATION include)