ccmake: Fix recent compilation regression with GCC on Solaris

The change in commit 32f756c8 (CursesDialog: include what you use,
2016-09-01) revealed that an ancient workaround for compiling with GCC
on Solaris has not had an effect in a long time and is now incorrect.
Drop it.

Source/CursesDialog/cmCursesStandardIncludes.h

@@ -14,10 +14,6 @@
 
 #include <cmConfigure.h>
 
-#if defined(__sun__) && defined(__GNUC__)
-#define _MSE_INT_H
-#endif
-
 #if defined(__hpux)
 #define _BOOL_DEFINED
 #include <sys/time.h>

Source/CursesDialog/form/form.h

@@ -33,10 +33,6 @@
 #ifndef FORM_H
 #define FORM_H
 
-#if defined(__sun__) && defined(__GNUC__)
- #define _MSE_INT_H
-#endif
-
 #include <cmFormConfigure.h>
 
 /* figure out which curses.h to include */