CMake external cache args

[gangliao]

增加CMake缓存变量, 使得CMake第一次编译第三方依赖中断的情况下，能够通过cache找到正确的值

[typhoonzero]

CMAKE_CACHE_ARGS 增加是否可以解决 #1674 出现的：/bin/sh: 1: eval: /usr/local/bin/cmake: Argument list too long的问题呢？ 从这里看到的：http://cmake-developers.cmake.narkive.com/BTV03NRr/externalproject-cmake-args-and-cmake-cache-args-arguments

[typhoonzero]

LGTM

[typhoonzero]

编译thirdparty/benchmark报错：

HEAD is now at 9f75c5a... Merge pull request #2337 from sergiocampama/deprecation
Submodule 'third_party/benchmark' (https://github.com/google/benchmark.git) registered for path 'third_party/benchmark'
Cloning into 'third_party/benchmark'...
In file included from ../../common.h:735:0,
                 from lauu2_U.c:40:
../../common_macro.h:43:22: error: ../../common_d.h: Invalid argument
 #include "common_d.h"
                      ^
lauu2_U.c: In function ‘dlauu2_U’:
lauu2_U.c:63:5: warning: implicit declaration of function ‘DSCAL_K’ [-Wimplicit-function-declaration]
     SCAL_K(i + 1, 0, 0, *(a + i + i * lda), a + i * lda, 1, NULL, 0, NULL, 0);
     ^
lauu2_U.c:66:7: warning: implicit declaration of function ‘DDOTU_K’ [-Wimplicit-function-declaration]
       aii = DOTU_K(n - i - 1, a + i + (i + 1)* lda, lda, a + i + (i + 1) * lda, lda);
       ^
lauu2_U.c:70:7: warning: implicit declaration of function ‘DGEMV_N’ [-Wimplicit-function-declaration]
       GEMV_N(i, n - i - 1, 0, dp1,
       ^
make[5]: *** [dlauu2_U.o] Error 1
make[5]: *** Waiting for unfinished jobs....
make[4]: *** [libs] Error 1
make[3]: *** [libs] Error 1
make[2]: *** [../third_party/openblas/src/openblas-stamp/openblas-build] Error 2
make[1]: *** [CMakeFiles/openblas.dir/all] Error 2
make[1]: *** Waiting for unfinished jobs....
Submodule path 'third_party/benchmark': checked out '360e66c1c4777c99402cf8cd535aa510fee16573'

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应该和openblas的问题有关系不影响这个PR的merge

[gangliao]

@typhoonzero make VERBOSE=1 看起来是openblas的问题
?