BUG: Correct DIFFPY_VERSION macro in scons.

Problem: For alpha releases DIFFPY_VERSION is a `(N - 500)`
expression so appending `LL` to force `long long` is invalid.

Solution: Append `LL` in the scons script that resolves the version.

Author: pavoljuhas

src/diffpy/SConscript.version

@@ -26,7 +26,7 @@ def build_VersionCode(target, source, env):
     assert numversion // 1000000 % 1000 == ginfo['minor'], emsg
     assert numversion // 1000 % 1000 == ginfo['micro'], emsg
     assert numversion % 500 == ginfo['patchnumber'], emsg
-    libversion = str(numversion)
+    libversion = str(numversion) + "LL"
     if ginfo['prerelease']:
         libversion = "(-500 + %s)" % libversion
     flds = {

src/diffpy/version.cpp

@@ -18,11 +18,7 @@
 
 #include <diffpy/version.hpp>
 
-// Append LL suffix to the DIFFPY_VERSION number.
-#define APPEND(x, y) x ## y
-#define LL(x) APPEND(x, LL)
-
-const long long libdiffpy_version_info::version = LL(DIFFPY_VERSION);
+const long long libdiffpy_version_info::version = DIFFPY_VERSION;
 const char* libdiffpy_version_info::version_str = DIFFPY_VERSION_STR;
 const int libdiffpy_version_info::major = DIFFPY_VERSION_MAJOR;
 const int libdiffpy_version_info::minor = DIFFPY_VERSION_MINOR;