Use input file for configure_file

This is so we can potentially add comments to it, and so if a user looks
at the installed header, they can see the /* #undef WLR_HAS_FEATURE */
line to see every option, even if not available.

include/wlr/config.h.in

@@ -0,0 +1,19 @@
+#ifndef WLR_CONFIG_H
+#define WLR_CONFIG_H
+
+#mesondefine WLR_HAS_LIBCAP
+
+#mesondefine WLR_HAS_SYSTEMD
+#mesondefine WLR_HAS_ELOGIND
+
+#mesondefine WLR_HAS_X11_BACKEND
+
+#mesondefine WLR_HAS_XWAYLAND
+
+#mesondefine WLR_HAS_XCB_ERRORS
+#mesondefine WLR_HAS_XCB_ICCCM
+#mesondefine WLR_HAS_XCB_XKB
+
+#mesondefine WLR_HAS_POSIX_FALLOCATE
+
+#endif

include/wlr/meson.build

@@ -4,14 +4,13 @@ version_data.set_quoted('WLR_VERSION_STR',   meson.project_version())
 version_data.set('WLR_VERSION_MAJOR',        version_array[0])
 version_data.set('WLR_VERSION_MINOR',        version_array[1])
 version_data.set('WLR_VERSION_MICRO',        version_array[2])
-version_data.set('WLR_VERSION_NUM',          '(WLR_VERSION_MAJOR << 16) | (WLR_VERSION_MINOR << 8) | WLR_VERSION_MICRO')
 version_data.set('WLR_VERSION_API_CURRENT',  so_version[0])
 version_data.set('WLR_VERSION_API_REVISION', so_version[1])
 version_data.set('WLR_VERSION_API_AGE',      so_version[2])
 
 install_headers(
-	configure_file(output: 'config.h',  configuration: conf_data),
-	configure_file(output: 'version.h', configuration: version_data),
+	configure_file(input: 'config.h.in', output: 'config.h',configuration: conf_data),
+	configure_file(input: 'version.h.in', output: 'version.h', configuration: version_data),
 	'backend.h',
 	'xcursor.h',
 	subdir: 'wlr'

include/wlr/version.h.in

@@ -0,0 +1,16 @@
+#ifndef WLR_VERSION_H
+#define WLR_VERSION_H
+
+#mesondefine WLR_VERSION_STR
+
+#mesondefine WLR_VERSION_MAJOR
+#mesondefine WLR_VERSION_MINOR
+#mesondefine WLR_VERSION_MICRO
+
+#define WLR_VERSION_NUM ((WLR_VERSION_MAJOR << 16) | (WLR_VERSION_MINOR << 8) | WLR_VERSION_MICRO)
+
+#mesondefine WLR_VERSION_API_CURRENT
+#mesondefine WLR_VERSION_API_REVISION
+#mesondefine WLR_VERSION_API_AGE
+
+#endif