build libpng from source

.gitignore

@@ -0,0 +1,2 @@
+subprojects/packagecache
+subprojects/libpng-1.6.37

meson.build

@@ -63,8 +63,11 @@ src_tests = [
 
 thread_dep = dependency('threads')
 glew_dep = dependency('glew')
+
+png_proj = subproject('libpng')
+png_dep = png_proj.get_variable('libpng_dep')
+
 glfw_dep = dependency('glfw3')
-png_dep = dependency('libpng')
 
 args = ['-Wall', '-Wextra', '-pedantic', '-Werror']
 

subprojects/libpng.wrap

@@ -0,0 +1,11 @@
+[wrap-file]
+directory = libpng-1.6.37
+source_url = https://github.com/glennrp/libpng/archive/v1.6.37.tar.gz
+source_filename = libpng-1.6.37.tar.gz
+source_hash = ca74a0dace179a8422187671aee97dd3892b53e168627145271cad5b5ac81307
+patch_url = https://wrapdb.mesonbuild.com/v1/projects/libpng/1.6.37/3/get_zip
+patch_filename = libpng-1.6.37-3-wrap.zip
+patch_hash = 6c9f32fd9150b3a96ab89be52af664e32207e10aa9f5fb9aa015989ee2dd7100
+
+[provide]
+libpng = libpng_dep