Description:
------------
I am getting lots of unresolved externals when I try to compile PHP7 with VC14 (VC 2015).

I started with a clean sheet and VC 2015 Pro RC. I used the deps from http://windows.php.net/downloads/php-sdk/deps-5.6-vc11-x86.7z as starting point. With those deps a lot of extensions did not compile.

I recompiled mcrypt, iconv, xml2, ssleay32, libeay32, ssh2, curl, xpm, zlib, jpeg, png, vpx, libbz2, netsnmp (all x86 vc14) to get rid of many problems. But I was really surprised recompilation if the libs was needed. Some still remain, like php_gmp.dll, which fails on the mpir_a.lib in the VC11 deps for 5.6.

Error messages below.

Test script:
---------------
Recreating build dirs
Recreating build dirs
Recreating build dirs
libiconv_a.lib(iconv1.obj) : MSIL .netmodule or module compiled with /GL found; restarting link with /LTCG; add /LTCG to the link command line to improve linker performance
   Creating library C:\php-sdk\php70dev\Release_TS\php7ts.lib and object C:\php-sdk\php70dev\Release_TS\php7ts.exp
Generating code
Finished generating code
   Creating library C:\php-sdk\php70dev\Release_TS\php_gmp.lib and object C:\php-sdk\php70dev\Release_TS\php_gmp.exp
LINK : warning LNK4098: defaultlib 'LIBCMT' conflicts with use of other libs; use /NODEFAULTLIB:library
mpir_a.lib(memory.obj) : error LNK2019: unresolved external symbol ___iob_func referenced in function ___gmp_default_allocate
mpir_a.lib(assert.obj) : error LNK2001: unresolved external symbol ___iob_func
C:\php-sdk\php70dev\Release_TS\php_gmp.dll : fatal error LNK1120: 1 unresolved externals


Expected result:
----------------
I expected that VC14 would build with the deps that work fine for VC11 and VC12

Actual result:
--------------
Broken compilation for lots of extensions (and even the core before I recompiled some libs).