Vendor raptor source files (was embedded gitlink)

Tree vendored at upstream 0019c5dd; origin + license recorded in
raptor/VENDOR.txt. Windows SDL dev packages excluded via .gitignore.

raptor/include/SDL2-devel-2.28.2-mingw/SDL2-2.28.2/test/Makefile.os2

@@ -0,0 +1,19 @@
+# Open Watcom makefile to build SDL2 tests for OS/2
+# wmake -f Makefile.os2
+#
+# To error out upon warnings: wmake -f Makefile.os2 ENABLE_WERROR=1
+
+SYSTEM = os2v2
+
+INCPATH = -I"$(%WATCOM)/h/os2" -I"$(%WATCOM)/h"
+
+CFLAGS = -bt=os2 -d0 -q -bm -5s -fp5 -fpi87 -sg -oteanbmier -ei
+CFLAGS+= -wx -wcd=303
+CFLAGS+= -DHAVE_SIGNAL_H
+!ifeq ENABLE_WERROR 1
+CFLAGS+= -we
+!endif
+
+TNSRCS = testnative.c testnativeos2.c
+
+!include watcom.mif