Use -Og or equivalent for debug builds

Unless minimal cflags is set add -Og or equivalent to CXXFLAGS for debug
build configuration.

Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>

build/premake/premake5.lua

@@ -188,6 +188,11 @@ function project_set_build_flags()
 	filter { "Debug", "action:vs*" }
 		defines { "DEBUG" }
 
+	filter { "Debug" }
+		if os.istarget("windows") or not _OPTIONS["minimal-flags"] then
+			optimize "Debug"
+		end
+
 	filter "Release"
 		if os.istarget("windows") or not _OPTIONS["minimal-flags"] then
 			optimize "Speed"