build: build libplatsch as dedicated library

This adds the support for building platsch and libplatsch. Platsch links
uses the static library to not cause any performance regression.

By this commit the conversion from a standalone application into an
application and library is complete.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>

meson.build

@@ -10,10 +10,28 @@ project(
 
 libdrm_dep = dependency('libdrm', version : '>=2.4.112')
 
+install_headers('libplatsch.h')
+
+platsch_lib = both_libraries(
+  'platsch',
+  sources : ['libplatsch.c'],
+  dependencies : [libdrm_dep],
+  install : true,
+)
+
+pkg_mod = import('pkgconfig')
+pkg_mod.generate(
+  libraries : platsch_lib,
+  version : '2024.06.0',
+  name : 'libplatsch',
+  filebase : 'platsch',
+  description : 'A Library to build custom bootsplash applications.'
+)
+
 executable(
   'platsch', 
-  sources : ['platsch.c', 'libplatsch.c'],
-  dependencies : [libdrm_dep],
+  sources : ['platsch.c'],
+  link_with : platsch_lib.get_static_lib(),
   install : true,
   install_dir : get_option('sbindir'),
 )