build: Add Meson build files

Meson is a Python-based build system that generates build rules of
Ninja, Visual Studio, and XCode. It's designed to be fast, and have a
small, non-Turing complete language to describe the build process,
tests, and dependencies. It's simpler than CMake, and faster than
autotools.

As a direct comparison in terms of speed, three build and check runs for
libepoxy from a clean Git repository clone yield these results on my
Kabylake Core i7 7500U (nproc=4):

- Autotools (make)
Run #1 (cold)   real: 22.384s, user: 20.011s, sys: 3.689s
Run #2 (warm)   real: 22.429s, user: 20.220s, sys: 3.708s
Run #3 (warm)   real: 22.068s, user: 19.743s, sys: 3.594s

- Meson (ninja)
Run #1 (cold)   real: 5.932s, user:  9.371s, sys: 1.625s
Run #2 (warm)   real: 6.273s, user: 10.066,  sys: 1.740s
Run #3 (warm)   real: 5.796s, user:  9.233s, sys: 1.607s

Which means that Meson and ninja are approximately 4x faster than
autotools.

In terms of simplicity, the autotools build takes six files and a total
of 645 lines; Meson requires 3 files, and 361 lines to achieve the same
result. Additionally, Meson automatically builds in a separate build
directory and does not leave files inside the source directory; and Meson
does not use libtool.

Since Meson is quite new and still actively developed, we're going to
leave the autotools build in place for a while, with the intention of
switching to Meson in the future.

1 files changed, 88 insertions, 0 deletions

diff --git a/src/meson.build b/src/meson.build
new file mode 100644
index 0000000..1ca4117
--- /dev/null
+++ b/src/meson.build
@@ -0,0 +1,88 @@
+common_sources = [
+  'dispatch_common.c',
+  'dispatch_common.h',
+]
+
+# Configuration file
+configure_file(output: 'config.h', configuration: conf)
+
+# Generate the dispatch tables
+gen_dispatch_py = find_program('gen_dispatch.py')
+
+gen_dispatch = generator(gen_dispatch_py,
+			 output: [ '@BASENAME@_generated.h', '@BASENAME@_generated_dispatch.c', ],
+                         arguments: [ '--dir=@BUILD_DIR@', '@INPUT@' ])
+
+gl_generated = gen_dispatch.process(join_paths(meson.source_root(), 'registry/gl.xml'))
+gl_headers = [ join_paths(meson.source_root(), 'include/epoxy/gl.h'), 'gl_generated.h', ]
+gl_sources = gl_generated
+
+egl_headers = []
+egl_sources = []
+if build_egl
+  egl_generated = gen_dispatch.process(join_paths(meson.source_root(), 'registry/egl.xml'))
+  egl_headers += [ join_paths(meson.source_root(), 'include/epoxy/egl.h'), 'egl_generated.h', ]
+  egl_sources += [ egl_generated, 'dispatch_egl.c', ]
+endif
+
+glx_headers = []
+glx_sources = []
+if build_glx
+  glx_generated = gen_dispatch.process(join_paths(meson.source_root(), 'registry/glx.xml'))
+  glx_headers += [ join_paths(meson.source_root(), 'include/epoxy/glx.h'), 'glx_generated.h', ]
+  glx_sources += [ glx_generated, 'dispatch_glx.c', ]
+endif
+
+wgl_headers = []
+wgl_sources = []
+if build_wgl
+  wgl_generated = gen_dispatch.process(join_paths(meson.source_root(), 'registry/wgl.xml'))
+  wgl_headers += [ join_paths(meson.source_root(), 'include/epoxy/wgl.h'), 'wgl_generated.h', ]
+  wgl_sources += [ wgl_generated, 'dispatch_wgl.c', ]
+endif
+
+if cc.get_id() == 'msvc'
+  common_ldflags = []
+else
+  common_ldflags = [ '-Wl,-Bsymbolic', ]
+endif
+
+epoxy_deps = [ dl_dep, ]
+if host_system == 'windows'
+  ogl_dep = cc.find_library('opengl32', required: true)
+  epoxy_deps += [ ogl_dep, ]
+endif
+
+libepoxy_inc = [ epoxy_include, include_directories('.'), ]
+
+# Allow building a static version of epoxy
+libtype = get_option('default_library')
+
+if libtype != 'shared'
+  libepoxy_static = static_library('epoxy',
+                                   common_sources + [ gl_sources, egl_sources, glx_sources, wgl_sources ],
+                                   install: true,
+                                   dependencies: epoxy_deps,
+                                   include_directories: libepoxy_inc,
+                                   c_args: common_cflags,
+                                   link_args: common_ldflags)
+  libepoxy = libepoxy_static
+endif
+
+if libtype != 'static'
+  libepoxy_shared = shared_library('epoxy',
+                                   sources: common_sources + [ gl_sources, egl_sources, glx_sources, wgl_sources ],
+                                   version: '0.0.0',
+                                   install: true,
+                                   dependencies: epoxy_deps,
+                                   include_directories: libepoxy_inc,
+                                   c_args: common_cflags,
+                                   link_args: common_ldflags)
+  libepoxy = libepoxy_shared
+endif
+
+libepoxy_dep = declare_dependency(link_with: libepoxy,
+                                  include_directories: libepoxy_inc,
+                                  dependencies: dl_dep)
+
+install_headers(gl_headers + glx_headers + egl_headers + wgl_headers, subdir: 'epoxy')