build: make imgui a submodule instead of copying it

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "external"]
 	path = external
 	url = ../../lolengine/lol-external.git
+[submodule "src/3rdparty/imgui"]
+	path = src/3rdparty/imgui
+	url = ../../lolengine/imgui.git

build/autotools/m4/lol-conf.m4

@@ -86,7 +86,7 @@ fi
 
 dnl  Use Imgui? Yes, always
 if true; then
-  LOL_CFLAGS="$LOL_CFLAGS -I\$(lol_srcdir)/external/imgui"
+  LOL_CFLAGS="$LOL_CFLAGS -I\$(lol_srcdir)/src/3rdparty/imgui"
 fi
 
 

build/lol-build

@@ -263,7 +263,7 @@ configure()
             CPPFLAGS="$CPPFLAGS -I$PWD/external/gtk-2.22.1/include/gdk-pixbuf-2.0"
             CPPFLAGS="$CPPFLAGS -I$PWD/external/gtk-2.22.1/include/atk-1.0"
             CPPFLAGS="$CPPFLAGS -I$PWD/external/gtkglarea-2.0.1/include"
-            CPPFLAGS="$CPPFLAGS -I$PWD/external/imgui/include"
+            CPPFLAGS="$CPPFLAGS -I$PWD/src/3rdparty/imgui/include"
             CPPFLAGS="$CPPFLAGS -mms-bitfields"
             LDFLAGS="$LDFLAGS -static-libgcc -static-libstdc++"
             GTK_LIBS="$GTK_LIBS -lgtkgl-2.0 -lopengl32 -lglew32 -lgdi32"

build/msbuild/lol.vars.props

@@ -9,7 +9,7 @@
     <PegtlIncludes>$(PegtlDir)\include</PegtlIncludes>
 
     <!-- imgui -->
-    <ImguiDir>$(ExternalDir)\imgui</ImguiDir>
+    <ImguiDir>$(LolDir)\src\3rdparty\imgui</ImguiDir>
     <ImguiIncludes>$(ImguiDir)</ImguiIncludes>
 
     <!-- libgcc (from mingw-w64) -->

external

@@ -1 +1 @@
-Subproject commit 88ebbc99e2ed7e9f93b8e336dce7b1e08a776551
+Subproject commit 406ad09301126c1d80c08179973589fe8930162c

src/3rdparty/imgui

@@ -0,0 +1 @@
+Subproject commit 0123fc8c0f3f9b9d55b31d7403dea32d568032fe