--- a/configure.in
+++ b/configure.in
@@ -7502,64 +7502,72 @@ else
   *-netbsd*)
     AC_DEFINE(MOZ_MEMORY_BSD)
     ;;
   *-solaris*)
     AC_DEFINE(MOZ_MEMORY_SOLARIS)
     ;;
   *-mingw*)
     AC_DEFINE(MOZ_MEMORY_WINDOWS)
-    AC_MSG_CHECKING([for VC2005/2008++ CRT source])
+    dnl This is sort of awful. Will revisit if we add support for more versions
     if test "$CC_VERSION" == "14.00.50727.762" -o "$CC_VERSION" == "15.00.30729.01"; then
-      if test -z "$WIN32_CRT_SRC_DIR" -a -n "$VCINSTALLDIR"; then
+      WIN32_OLD_STYLE_JEMALLOC=1
+      AC_DEFINE(WIN32_OLD_STYLE_JEMALLOC)
+    elif test "$CC_VERSION" == "16.00.30319.01" -o "$CC_VERSION" == "16.00.40219.01"; then
+      WIN32_NEW_STYLE_JEMALLOC=1
+      AC_DEFINE(WIN32_NEW_STYLE_JEMALLOC)
+    else        
+      AC_MSG_ERROR([Building jemalloc requires exactly Visual C++ 2005 SP1 or 2008 SP1 or 2010 currently.])
+    fi
+    if test -z "$WIN32_CRT_SRC_DIR" -a -n "$WIN32_OLD_STYLE_JEMALLOC"; then
+      if test -z "$VCINSTALLDIR" -o ! -d "$VCINSTALLDIR"; then
+        AC_MSG_ERROR([When building jemalloc, set WIN32_CRT_SRC_DIR to the path to the Visual C++ CRT source (usually VCINSTALLDIR\crt\src, but VCINSTALLDIR is not set, so I can't autodetect it for you).])
+      else
         WIN32_CRT_SRC_DIR="$VCINSTALLDIR\crt\src"
       fi
-      if test -n "$WIN32_CRT_SRC_DIR" -a -d "$WIN32_CRT_SRC_DIR"; then
-        AC_MSG_RESULT([yes])
-        WIN32_OLD_STYLE_JEMALLOC=1
-        WIN32_CRT_SRC_DIR=`cd "$WIN32_CRT_SRC_DIR" && pwd -W`
-        _objdir_win=`pwd -W`
-        WIN32_CUSTOM_CRT_DIR="$_objdir_win/memory/jemalloc/crtsrc/build/$MOZ_CRT_CPU_ARCH"
-        MOZ_MEMORY_LDFLAGS="-MANIFEST:NO -LIBPATH:\"$WIN32_CUSTOM_CRT_DIR\" -NODEFAULTLIB:msvcrt -NODEFAULTLIB:msvcrtd -NODEFAULTLIB:msvcprt -NODEFAULTLIB:msvcprtd -DEFAULTLIB:mozcrt19 -DEFAULTLIB:mozcpp19"
-      fi
-    fi
-    if test -z "$WIN32_OLD_STYLE_JEMALLOC"; then
-      AC_MSG_RESULT([no])
-      WIN32_NEW_STYLE_JEMALLOC=1
-      AC_DEFINE(WIN32_NEW_STYLE_JEMALLOC)
-      if test -z "$MOZ_DEBUG"; then
-        WIN32_CRT_LIBS="msvcrt.lib msvcprt.lib"
-      else
-        WIN32_CRT_LIBS="msvcrtd.lib msvcprtd.lib"
-      fi
-      dnl Look for a broken crtdll.obj
-      WIN32_CRTDLL_FULLPATH=`lib -nologo -list $WIN32_CRT_LIBS | grep crtdll\\.obj`
-      lib -NOLOGO -OUT:crtdll.obj $WIN32_CRT_LIBS -EXTRACT:$WIN32_CRTDLL_FULLPATH
-      if grep -q __imp__\{0,1\}free crtdll.obj; then
-        MOZ_MEMORY_LDFLAGS='-MANIFEST:NO -LIBPATH:$(DIST)/lib -NODEFAULTLIB:msvcrt -NODEFAULTLIB:msvcrtd -NODEFAULTLIB:msvcprt -NODEFAULTLIB:msvcprtd -DEFAULTLIB:mozcrt'
-      else
-        MOZ_MEMORY_LDFLAGS='$(DIST)/../memory/jemalloc/jemalloc.lib'
-      fi
-      rm crtdll.obj
     fi
     dnl cpu check
     case "${target_cpu}" in
     i*86)
       MOZ_CRT_CPU_ARCH=intel
       ;;
     x86_64)
       MOZ_CRT_CPU_ARCH=amd64
       ;;
     *)
       AC_MSG_ERROR([--enable-jemalloc not supported on ${target}])
       ;;
     esac
 
     AC_SUBST(MOZ_CRT_CPU_ARCH)
 
+    if test -n "$WIN32_OLD_STYLE_JEMALLOC"; then
+      if test ! -d "$WIN32_CRT_SRC_DIR"; then
+        AC_MSG_ERROR([Invalid Win32 CRT source directory: ${WIN32_CRT_SRC_DIR}])
+      fi
+      WIN32_CRT_SRC_DIR=`cd "$WIN32_CRT_SRC_DIR" && pwd -W`
+      _objdir_win=`pwd -W`
+      WIN32_CUSTOM_CRT_DIR="$_objdir_win/memory/jemalloc/crtsrc/build/$MOZ_CRT_CPU_ARCH"
+      MOZ_MEMORY_LDFLAGS="-MANIFEST:NO -LIBPATH:\"$WIN32_CUSTOM_CRT_DIR\" -NODEFAULTLIB:msvcrt -NODEFAULTLIB:msvcrtd -NODEFAULTLIB:msvcprt -NODEFAULTLIB:msvcprtd -DEFAULTLIB:mozcrt19 -DEFAULTLIB:mozcpp19"
+    else
+      if test -z "$MOZ_DEBUG"; then
+        WIN32_CRT_LIBS="msvcrt.lib msvcprt.lib"
+      else
+        WIN32_CRT_LIBS="msvcrtd.lib msvcprtd.lib"
+      fi
+      dnl Look for a broken crtdll.obj
+      WIN32_CRTDLL_FULLPATH=`lib -list $WIN32_CRT_LIBS | grep crtdll\\.obj`
+      lib -OUT:crtdll.obj $WIN32_CRT_LIBS -EXTRACT:$WIN32_CRTDLL_FULLPATH
+      if grep -q '__imp__\{0,1\}free' crtdll.obj; then
+        MOZ_MEMORY_LDFLAGS='-MANIFEST:NO -LIBPATH:$(DIST)/lib -NODEFAULTLIB:msvcrt -NODEFAULTLIB:msvcrtd -NODEFAULTLIB:msvcprt -NODEFAULTLIB:msvcprtd -DEFAULTLIB:mozcrt'
+      else
+        MOZ_MEMORY_LDFLAGS='$(DIST)/../memory/jemalloc/jemalloc.lib'
+      fi
+      rm crtdll.obj
+    fi
     dnl Also pass this to NSPR/NSS
     DLLFLAGS="$DLLFLAGS $MOZ_MEMORY_LDFLAGS"
     export DLLFLAGS
     ;;
   *)
     AC_MSG_ERROR([--enable-jemalloc not supported on ${target}])
     ;;
   esac

--- a/memory/jemalloc/Makefile.in
+++ b/memory/jemalloc/Makefile.in
@@ -206,41 +206,43 @@ ifndef WIN32_OLD_STYLE_JEMALLOC
 # back together with the patched crtdll.obj, glue it to the end of jemalloc's
 # import library and link the rest of Mozilla to that.
 #
 # The result?  A binary that uses jemalloc, doesn't crash, and leaks a tiny
 # amount of memory (32 words per DLL in the 2010 CRT) at shutdown.
 #
 ###############################################################################
 
-libs:: mozcrt.lib
+libs:: $(DIST)/lib/mozcrt.lib
+
+$(DIST)/lib/mozcrt.lib:: mozcrt.lib
 	$(INSTALL) $(IFLAGS2) mozcrt.lib $(DIST)/lib
 
 # And finally combine that with the jemalloc import library to get an import
 # library that has our malloc/free/etc and the CRT's everything else
-mozcrt.lib: $(IMPORT_LIBRARY) msvc_modified.lib
+mozcrt.lib:: $(IMPORT_LIBRARY) msvc_modified.lib
 	lib -OUT:$@ $^
 
 # Put the fixed object file back in
-msvc_modified.lib: msvc_removed.lib crtdll_fixed.obj
+msvc_modified.lib:: msvc_removed.lib crtdll_fixed.obj
 	lib -OUT:$@ $^
 
 # Fix the object file
-crtdll_fixed.obj: crtdll.obj
+crtdll_fixed.obj:: crtdll.obj
 	$(PYTHON) $(srcdir)/fixcrt.py
 
 # Find the path of crtdll.obj
 CRTDLL_FULLPATH=$(subst \,\\,$(shell lib -list msvc_combined.lib | grep crtdll\\.obj))
 
 # Remove the broken object file, only after we have extracted it
-msvc_removed.lib: msvc_combined.lib crtdll.obj
+msvc_removed.lib:: msvc_combined.lib crtdll.obj
 	lib -OUT:$@ msvc_combined.lib -REMOVE:$(CRTDLL_FULLPATH)
 
 # Extract the broken object file out of the combined library
-crtdll.obj: msvc_combined.lib
+crtdll.obj:: msvc_combined.lib
 	lib -OUT:$@ $^ -EXTRACT:$(CRTDLL_FULLPATH)
 
 # Grab both CRT libraries and combine them into one library to simplify things
-msvc_combined.lib:
+msvc_combined.lib::
 	lib -OUT:$@ $(WIN32_CRT_LIBS)
 
 endif
 endif