cmath and complex alter the contents of the TU when building implicitly modules.

Clang implicitly builds modules upon seeing header files present in the module
map. Having cmath before alters the contents of the TU (by defining macros
which affect building the modules).

roofit/roofit/inc/RooGaussModel.h

@@ -16,13 +16,13 @@
 #ifndef ROO_GAUSS_MODEL
 #define ROO_GAUSS_MODEL
 
-#include <cmath>
-#include <complex>
-
 #include "RooResolutionModel.h"
 #include "RooRealProxy.h"
 #include "RooMath.h"
 
+#include <cmath>
+#include <complex>
+
 class RooGaussModel : public RooResolutionModel {
 public: