Examples: Fix MinGW detection in makefiles. Fix example_null build due to missing IME input libs. (#2590)
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 888593e..8cd056c 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -68,7 +68,7 @@
           #include "examples/example_null/main.cpp"
 
           EOF
-          g++ -I. -Wall -Wformat -o example_single_file.exe example_single_file.cpp
+          g++ -I. -Wall -Wformat -o example_single_file.exe example_single_file.cpp -limm32
 
       - name: Build example_null (with IMGUI_DISABLE_WIN32_FUNCTIONS)
         shell: bash
@@ -81,7 +81,7 @@
           #include "examples/example_null/main.cpp"
 
           EOF
-          g++ -I. -Wall -Wformat -o example_single_file.exe example_single_file.cpp
+          g++ -I. -Wall -Wformat -o example_single_file.exe example_single_file.cpp -limm32
 
       - name: Build example_null (as DLL)
         shell: cmd
diff --git a/examples/example_glfw_opengl2/Makefile b/examples/example_glfw_opengl2/Makefile
index a24a91f..720a403 100644
--- a/examples/example_glfw_opengl2/Makefile
+++ b/examples/example_glfw_opengl2/Makefile
@@ -49,7 +49,7 @@
 	CFLAGS = $(CXXFLAGS)
 endif
 
-ifeq ($(findstring MINGW,$(UNAME_S)),MINGW)
+ifeq ($(OS), Windows_NT)
 	ECHO_MESSAGE = "MinGW"
 	LIBS += -lglfw3 -lgdi32 -lopengl32 -limm32
 
diff --git a/examples/example_glfw_opengl3/Makefile b/examples/example_glfw_opengl3/Makefile
index 294d103..83fdcf0 100644
--- a/examples/example_glfw_opengl3/Makefile
+++ b/examples/example_glfw_opengl3/Makefile
@@ -79,7 +79,7 @@
 	CFLAGS = $(CXXFLAGS)
 endif
 
-ifeq ($(findstring MINGW,$(UNAME_S)),MINGW)
+ifeq ($(OS), Windows_NT)
 	ECHO_MESSAGE = "MinGW"
 	LIBS += -lglfw3 -lgdi32 -lopengl32 -limm32
 
diff --git a/examples/example_glut_opengl2/Makefile b/examples/example_glut_opengl2/Makefile
index 952ca31..a980f56 100644
--- a/examples/example_glut_opengl2/Makefile
+++ b/examples/example_glut_opengl2/Makefile
@@ -40,7 +40,7 @@
 	CFLAGS = $(CXXFLAGS)
 endif
 
-ifeq ($(findstring MINGW,$(UNAME_S)),MINGW)
+ifeq ($(OS), Windows_NT)
 	ECHO_MESSAGE = "MinGW"
 	LIBS += -lgdi32 -lopengl32 -limm32
 ifeq ($(shell pkg-config freeglut --exists 2> /dev/null && echo yes || echo no),yes)
diff --git a/examples/example_null/Makefile b/examples/example_null/Makefile
index d4159e4..2197c01 100644
--- a/examples/example_null/Makefile
+++ b/examples/example_null/Makefile
@@ -57,12 +57,12 @@
 	CFLAGS = $(CXXFLAGS)
 endif
 
-ifeq ($(findstring MINGW,$(UNAME_S)),MINGW)
+ifeq ($(OS), Windows_NT)
 	ECHO_MESSAGE = "MinGW"
 	ifneq ($(WITH_EXTRA_WARNINGS), 0)
 		CXXFLAGS += -Wextra -Wpedantic
-		LIBS += -limm32
 	endif
+	LIBS += -limm32
 	CFLAGS = $(CXXFLAGS)
 endif
 
diff --git a/examples/example_null/build_win32.bat b/examples/example_null/build_win32.bat
index 38e7914..0cdfdc9 100644
--- a/examples/example_null/build_win32.bat
+++ b/examples/example_null/build_win32.bat
@@ -1,3 +1,3 @@
 @REM Build for Visual Studio compiler. Run your copy of vcvars32.bat or vcvarsall.bat to setup command-line compiler.
 mkdir Debug
-cl /nologo /Zi /MD /I ..\.. %* *.cpp ..\..\*.cpp /FeDebug/example_null.exe /FoDebug/ /link gdi32.lib shell32.lib
+cl /nologo /Zi /MD /I ..\.. %* *.cpp ..\..\*.cpp /FeDebug/example_null.exe /FoDebug/ /link gdi32.lib shell32.lib imm32.lib
diff --git a/examples/example_sdl_opengl2/Makefile b/examples/example_sdl_opengl2/Makefile
index 5fdad0b..92e0554 100644
--- a/examples/example_sdl_opengl2/Makefile
+++ b/examples/example_sdl_opengl2/Makefile
@@ -48,7 +48,7 @@
 	CFLAGS = $(CXXFLAGS)
 endif
 
-ifeq ($(findstring MINGW,$(UNAME_S)),MINGW)
+ifeq ($(OS), Windows_NT)
 	ECHO_MESSAGE = "MinGW"
 	LIBS += -lgdi32 -lopengl32 -limm32 `pkg-config --static --libs sdl2`
 
diff --git a/examples/example_sdl_opengl3/Makefile b/examples/example_sdl_opengl3/Makefile
index 6e30a13..7c0e7ea 100644
--- a/examples/example_sdl_opengl3/Makefile
+++ b/examples/example_sdl_opengl3/Makefile
@@ -78,12 +78,12 @@
 	CFLAGS = $(CXXFLAGS)
 endif
 
-ifeq ($(findstring MINGW,$(UNAME_S)),MINGW)
-   ECHO_MESSAGE = "MinGW"
-   LIBS += -lgdi32 -lopengl32 -limm32 `pkg-config --static --libs sdl2`
+ifeq ($(OS), Windows_NT)
+    ECHO_MESSAGE = "MinGW"
+    LIBS += -lgdi32 -lopengl32 -limm32 `pkg-config --static --libs sdl2`
 
-   CXXFLAGS += `pkg-config --cflags sdl2`
-   CFLAGS = $(CXXFLAGS)
+    CXXFLAGS += `pkg-config --cflags sdl2`
+    CFLAGS = $(CXXFLAGS)
 endif
 
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