Fix Windows build scripts for rolling releases.

Reported by Miku AuahDark.

src/msvcbuild.bat

@@ -42,7 +42,7 @@ if exist minilua.exe.manifest^
 minilua %DASM% -LN %DASMFLAGS% -o host\buildvm_arch.h vm_x86.dasc
 @if errorlevel 1 goto :BAD
 
-git show -s --format=%ct >luajit_relver.txt
+git show -s --format=%%ct >luajit_relver.txt
 minilua host\genversion.lua
 
 %LJCOMPILE% /I "." /I %DASMDIR% host\buildvm*.c

src/ps4build.bat

@@ -31,7 +31,7 @@ if exist minilua.exe.manifest^
 minilua %DASM% -LN %DASMFLAGS% -o host\buildvm_arch.h vm_x86.dasc
 @if errorlevel 1 goto :BAD
 
-git show -s --format=%ct >luajit_relver.txt
+git show -s --format=%%ct >luajit_relver.txt
 minilua host\genversion.lua
 
 %LJCOMPILE% /I "." /I %DASMDIR% -DLUAJIT_TARGET=LUAJIT_ARCH_X64 -DLUAJIT_OS=LUAJIT_OS_OTHER -DLUAJIT_DISABLE_JIT -DLUAJIT_DISABLE_FFI -DLUAJIT_NO_UNWIND host\buildvm*.c

src/psvitabuild.bat

@@ -31,7 +31,7 @@ if exist minilua.exe.manifest^
 minilua %DASM% -LN %DASMFLAGS% -o host\buildvm_arch.h vm_arm.dasc
 @if errorlevel 1 goto :BAD
 
-git show -s --format=%ct >luajit_relver.txt
+git show -s --format=%%ct >luajit_relver.txt
 minilua host\genversion.lua
 
 %LJCOMPILE% /I "." /I %DASMDIR% -DLUAJIT_TARGET=LUAJIT_ARCH_ARM -DLUAJIT_OS=LUAJIT_OS_OTHER -DLUAJIT_DISABLE_JIT -DLUAJIT_DISABLE_FFI -DLJ_TARGET_PSVITA=1 host\buildvm*.c

src/xedkbuild.bat

@@ -31,7 +31,7 @@ if exist minilua.exe.manifest^
 minilua %DASM% -LN %DASMFLAGS% -o host\buildvm_arch.h vm_ppc.dasc
 @if errorlevel 1 goto :BAD
 
-git show -s --format=%ct >luajit_relver.txt
+git show -s --format=%%ct >luajit_relver.txt
 minilua host\genversion.lua
 
 %LJCOMPILE% /I "." /I %DASMDIR% /D_XBOX_VER=200 /DLUAJIT_TARGET=LUAJIT_ARCH_PPC  host\buildvm*.c