meson: Add fallback discovery for libxml2 and sqlite3 on MSVC

The build system for Visual Studio for libxml2, as well as the typical
amalgamation sources for sqlite3 that is used for Visual Studio builds
do not generate pkg-config files.  So, on Visual Studio builds, we need
to manually look for these dependencies when their pkg-config files
cannot be found.

This is done because hand-crafting pkg-config files is a tedious process
that can be error-prone.

1 files changed, 20 insertions, 2 deletions

diff --git a/meson.build b/meson.build
index e667efa7..238876e3 100644
--- a/meson.build
+++ b/meson.build
@@ -28,9 +28,27 @@ glib_dep = [dependency('glib-2.0', version : '>=2.38'),
             dependency('gobject-2.0', version : '>=2.38'),
             dependency('gio-2.0', version : '>=2.38')]
 
-sqlite_dep = [dependency('sqlite3')]
+sqlite_dep = dependency('sqlite3', required: cc.get_id() != 'msvc')
+
+# Fallback check for sqlite on Visual Studio, which normally does not
+# generate a pkg-config file upon a successful build
+if not sqlite_dep.found()
+  cc.has_header('sqlite3.h')
+  cc.has_header('sqlite3ext.h')
+  sqlite_dep = cc.find_library('sqlite3')
+endif
+
+libxml_dep = dependency('libxml-2.0', required: cc.get_id() != 'msvc')
 
-libxml_dep = [dependency('libxml-2.0')]
+
+# Fallback check for libxml2 on Visual Studio, which normally does not
+# generate a pkg-config file upon a successful build
+if not libxml_dep.found()
+  # Note: The XML include dir needs to be within the INCLUDE envvar,
+  # such as <INCLUDEDIR>\libxml2
+  cc.has_header('libxml/tree.h')
+  libxml2_dep = cc.find_library('libxml2')
+endif
 
 cdata = configuration_data()