Merge #17817: build: Add default configure cache file to .gitignore

0661a3c build: Add default configure cache to .gitignore (Hennadii Stepanov)

Pull request description:

  Ref: [Autoconf - 7.4.2 Cache Files](https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/autoconf.html#Cache-Files)

ACKs for top commit:
  fanquake:
    ACK 0661a3c - sure; going to merge this. However lets not start adding every file that might occur from using any autoconf option to our .gitignore..

Tree-SHA512: 8be8fdd7fda35ae190c1613e5b3ac4860d6f9ec08f06b66b1278be26e11a1616ec781e0b88d0761690c99600b4de2306c01dd9798f9143531ddacb373e3fc677

Author: fanquake

.gitignore

@@ -28,6 +28,7 @@ build-aux/m4/ltversion.m4
 build-aux/missing
 build-aux/compile
 build-aux/test-driver
+config.cache
 config.log
 config.status
 configure