[FL-2052] New build system based on scons (#1269)

site_scons/site_tools/ccache.py

@@ -0,0 +1,14 @@
+def exists():
+    return True
+
+
+def generate(env):
+    if ccache := env.WhereIs("ccache"):
+        env["CCACHE"] = "ccache"
+        env["CC_NOCACHE"] = env["CC"]
+        env["CC"] = "$CCACHE $CC_NOCACHE"
+        # Tricky place: linking is done with CXX
+        # Using ccache breaks it
+        env["LINK"] = env["CXX"]
+        env["CXX_NOCACHE"] = env["CXX"]
+        env["CXX"] = "$CCACHE $CXX_NOCACHE"