begin adding gui sources; build .c files

wscript

@@ -2,17 +2,19 @@ import platform
 import re
 
 def options(opt):
-    opt.load("compiler_cxx")
+    opt.load("compiler_c compiler_cxx")
 
 def configure(conf):
-    conf.load("compiler_cxx")
+    conf.load("compiler_c compiler_cxx")
     conf.check(header_name = "getopt.h")
 
 def build(bld):
-    bld(features = "cxx cxxprogram",
+    bld(features = "c cprogram cxx cxxprogram",
         target = "jes",
-        source = bld.path.ant_glob("src/**/*.cc"),
+        source = bld.path.ant_glob(["src/**/*.cc", "src/**/*.c"]),
-        cxxflags = ["-Wall", "-std=gnu++14"])
+        cxxflags = ["-Wall", "-std=gnu++14"],
+        lib = ["dl", "GL"])
+
     test_libs = []
     if re.search(r'linux', platform.platform(), re.IGNORECASE):
         test_libs += ["pthread"]