Allow changing *.dll/*.lib name in msvcbuild.bat.

src/msvcbuild.bat

@@ -20,6 +20,8 @@
 @set LJLIB=lib /nologo
 @set DASMDIR=..\dynasm
 @set DASM=%DASMDIR%\dynasm.lua
+@set LJDLLNAME=lua51.dll
+@set LJLIBNAME=lua51.lib
 @set ALL_LIB=lib_base.c lib_math.c lib_bit.c lib_string.c lib_table.c lib_io.c lib_os.c lib_package.c lib_debug.c lib_jit.c lib_ffi.c
 
 %LJCOMPILE% host\minilua.c
@@ -70,27 +72,27 @@ buildvm -m folddef -o lj_folddef.h lj_opt_fold.c
 @if "%1"=="static" goto :STATIC
 %LJCOMPILE% /DLUA_BUILD_AS_DLL lj_*.c lib_*.c
 @if errorlevel 1 goto :BAD
-%LJLINK% /DLL /out:lua51.dll lj_*.obj lib_*.obj
+%LJLINK% /DLL /out:%LJDLLNAME% lj_*.obj lib_*.obj
 @if errorlevel 1 goto :BAD
 @goto :MTDLL
 :STATIC
 %LJCOMPILE% /DLUA_BUILD_AS_DLL lj_*.c lib_*.c
 @if errorlevel 1 goto :BAD
-%LJLIB% /OUT:lua51.lib lj_*.obj lib_*.obj
+%LJLIB% /OUT:%LJLIBNAME% lj_*.obj lib_*.obj
 @if errorlevel 1 goto :BAD
 @goto :MTDLL
 :AMALGDLL
 %LJCOMPILE% /DLUA_BUILD_AS_DLL ljamalg.c
 @if errorlevel 1 goto :BAD
-%LJLINK% /DLL /out:lua51.dll ljamalg.obj lj_vm.obj
+%LJLINK% /DLL /out:%LJDLLNAME% ljamalg.obj lj_vm.obj
 @if errorlevel 1 goto :BAD
 :MTDLL
-if exist lua51.dll.manifest^
-  %LJMT% -manifest lua51.dll.manifest -outputresource:lua51.dll;2
+if exist %LJDLLNAME%.manifest^
+  %LJMT% -manifest %LJDLLNAME%.manifest -outputresource:%LJDLLNAME%;2
 
 %LJCOMPILE% luajit.c
 @if errorlevel 1 goto :BAD
-%LJLINK% /out:luajit.exe luajit.obj lua51.lib
+%LJLINK% /out:luajit.exe luajit.obj %LJLIBNAME%
 @if errorlevel 1 goto :BAD
 if exist luajit.exe.manifest^
   %LJMT% -manifest luajit.exe.manifest -outputresource:luajit.exe