win32: improve build_coverity.cmd

ports/win32/msvc/build_coverity.cmd

@@ -1,17 +1,26 @@
 @echo off
-rem ATTENTION: this deletes the output folder first!
-set devenv="c:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\devenv"
-set covbuild=%1
-rem set covbuild=e:\Downloads\cov-analysis-win64-2017.07\bin\cov-build.exe
+rem Usage: pass the path to cov-build.exe (with trailing backslash, without the exe) as first parameter
+rem ATTENTION: this deletes the output folder "cov-int" and the output file "cov-int.zip" first!
+
+set devenv="%ProgramFiles%\Microsoft Visual Studio 10.0\Common7\IDE\devenv.exe"
+if not exist %devenv% set devenv="%ProgramFiles%\Microsoft Visual Studio 10.0\Common7\IDE\vcexpress.exe"
+if not exist %devenv% set devenv="%ProgramFiles(x86)%\Microsoft Visual Studio 10.0\Common7\IDE\devenv.exe"
+if not exist %devenv% set devenv="%ProgramFiles(x86)%\Microsoft Visual Studio 10.0\Common7\IDE\vcexpress.exe"
+set covbuild=%1cov-build.exe
 set covoutput=cov-int
 set zip7="c:\Program Files\7-Zip\7z.exe"
 
 pushd %~dp0
 
-rd /s /1 %covoutput%
-del %covoutput%.zip
+if exist %covoutput% rd /s /q %covoutput%
+if exist %covoutput%.zip del %covoutput%.zip
 
-%covbuild% --dir %covoutput% %devenv% lwip_test.sln /build Debug 
+%covbuild% --dir %covoutput% %devenv% lwip_test.sln /build Debug || goto error
 
+if exist %zip7% goto dozip
+echo error: 7zip not found at \"%zip7%
+goto error
+:dozip
 %zip7% a %covoutput%.zip %covoutput%
+:error
 popd