change default of MSVC edition to build with

Build script will iterate on Ent, Pro or Community, to find an
installation to prepare the environment with. If Community is used,
it'll warn about its license.

Author: bpintea

build.bat

@@ -204,11 +204,17 @@ REM CLEAN function: clean up the build dir before building
 
 REM SETUP function: set-up the build environment
 :SETUP
-	REM TODO: add some logic to detect available versions (Enterprise, Professional, Community)
-	REM TODO: add support for vcvarsall.bat (2015)
 	set RELEASE=2017
-	set EDITION=Community
-	call "C:\Program Files (x86)\Microsoft Visual Studio\%RELEASE%\%EDITION%\Common7\Tools\VsDevCmd.bat" -arch=!TARCH!
+	set EDITION=Professional
+	for %%e in (Enterprise, Professional, Community) do (
+		if exist "C:\Program Files (x86)\Microsoft Visual Studio\%RELEASE%\%%e\Common7\Tools\VsDevCmd.bat" (
+			if /i "%%e" == "Community" (
+				echo WARNING: Community edition is not licensed to build commerical projects.
+			)
+			call "C:\Program Files (x86)\Microsoft Visual Studio\%RELEASE%\%%e\Common7\Tools\VsDevCmd.bat" -arch=!TARCH!
+			break
+		)
+	)
 
 	goto:eof