Add PCRE to support regular expressions

Use regular expressions instead of Lua patterns for find and replace editor commands.

Syntax files can now use regex or Lua patterns as before keeping backward compatibility for plugins.

src/meson.build

@@ -3,6 +3,7 @@ lite_sources = [
     'api/cp_replace.c',
     'api/renderer.c',
     'api/renderer_font.c',
+    'api/regex.c',
     'api/system.c',
     'renderer.c',
     'renwindow.c',
@@ -18,7 +19,7 @@ endif
 executable('lite',
     lite_sources + lite_rc,
     include_directories: [lite_include, font_renderer_include],
-    dependencies: [lua_dep, sdl_dep, libm, libdl, libx11],
+    dependencies: [lua_dep, sdl_dep, pcre2_dep, libm, libdl, libx11],
     c_args: lite_cargs,
     link_with: libfontrenderer,
     link_args: lite_link_args,