PS4/PS5: Fix build scripts.

Thanks to Mathias Westerdahl.

src/ps4build.bat

@@ -51,7 +51,7 @@ if exist minilua.exe.manifest^
 minilua %DASM% -LN %DASMFLAGS% -o host\buildvm_arch.h %DASC%
 @if errorlevel 1 goto :BAD
 
-%LJCOMPILE% /I "." /I %DASMDIR% %GC64% -DLUAJIT_TARGET=LUAJIT_ARCH_X64 -DLUAJIT_OS=LUAJIT_OS_OTHER -DLUAJIT_DISABLE_JIT -DLUAJIT_DISABLE_FFI -DLUAJIT_NO_UNWIND host\buildvm*.c
+%LJCOMPILE% /I "." /I %DASMDIR% %GC64% -DLUAJIT_TARGET=LUAJIT_ARCH_X64 -DLUAJIT_OS=LUAJIT_OS_OTHER -DLUAJIT_DISABLE_JIT -DLUAJIT_DISABLE_FFI -DLUAJIT_USE_SYSMALLOC -DLUAJIT_NO_UNWIND host\buildvm*.c
 @if errorlevel 1 goto :BAD
 %LJLINK% /out:buildvm.exe buildvm*.obj
 @if errorlevel 1 goto :BAD
@@ -78,7 +78,7 @@ buildvm -m folddef -o lj_folddef.h lj_opt_fold.c
 @set LJLIB="%SCE_ORBIS_SDK_DIR%\host_tools\bin\orbis-ar" rcus
 @set INCLUDE=""
 
-orbis-as -o lj_vm.o lj_vm.s
+"%SCE_ORBIS_SDK_DIR%\host_tools\bin\orbis-as" -o lj_vm.o lj_vm.s
 
 @if "%1" neq "debug" goto :NODEBUG
 @shift

src/ps5build.bat

@@ -74,11 +74,11 @@ buildvm -m folddef -o lj_folddef.h lj_opt_fold.c
 @if errorlevel 1 goto :BAD
 
 @rem ---- Cross compiler ----
-@set LJCOMPILE="%SCE_PROSPERO_SDK_DIR%\host_tools\bin\prospero-clang" -c -Wall -DLUAJIT_DISABLE_FFI %GC64%
+@set LJCOMPILE="%SCE_PROSPERO_SDK_DIR%\host_tools\bin\prospero-clang" -c -Wall -DLUAJIT_DISABLE_FFI -DLUAJIT_USE_SYSMALLOC %GC64%
 @set LJLIB="%SCE_PROSPERO_SDK_DIR%\host_tools\bin\prospero-llvm-ar" rcus
 @set INCLUDE=""
 
-%SCE_PROSPERO_SDK_DIR%\host_tools\bin\prospero-llvm-as -o lj_vm.o lj_vm.s
+"%SCE_PROSPERO_SDK_DIR%\host_tools\bin\prospero-clang" -c -o lj_vm.o lj_vm.s
 
 @if "%1" neq "debug" goto :NODEBUG
 @shift