fix macOS headless build

Signed-off-by: falkTX <falktx@falktx.com>

.gitignore

@@ -18,6 +18,7 @@ compile_commands.json
 
 /bin/
 /build/
+/build-headless/
 /deps/surge-build/
 /documentation.pdf
 /jucewrapper/build/

include/OpenGL/gl.h

@@ -0,0 +1,39 @@
+/*
+ * DISTRHO Cardinal Plugin
+ * Copyright (C) 2021 Filipe Coelho <falktx@falktx.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 3 of
+ * the License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * For a full copy of the GNU General Public License see the LICENSE file.
+ */
+
+#pragma once
+
+#ifdef HEADLESS
+# define GL_COLOR_BUFFER_BIT 0
+# define GL_DEPTH_BUFFER_BIT 0
+# define GL_STENCIL_BUFFER_BIT 0
+# define GL_PROJECTION 0
+# define GL_TRIANGLES 0
+static inline void glBegin(int) {}
+static inline void glEnd() {}
+static inline void glColor3f(float, float, float) {}
+static inline void glVertex3f(float, float, float) {}
+static inline void glClear(int) {}
+static inline void glClearColor(double, double, double, double) {}
+static inline void glLoadIdentity() {}
+static inline void glMatrixMode(int) {}
+static inline void glOrtho(double, double, double, double, double, double) {}
+static inline void glViewport(double, double, double, double) {}
+typedef unsigned int GLuint;
+#else
+# include_next <OpenGL/gl.h>
+#endif

src/Makefile

@@ -282,7 +282,7 @@ clap: $(TARGETS)
 	$(MAKE) clap -C CardinalSynth $(CARDINAL_SYNTH_ARGS)
 
 clean:
-	rm -f $(TARGETS)
+	rm -f *.a
 	rm -rf $(BUILD_DIR)
 	$(MAKE) clean -C Cardinal
 	$(MAKE) clean -C CardinalFX $(CARDINAL_FX_ARGS)