meson: fix cross-compilation issues with gperf header file preprocessing

Pass c_args to the compiler when preprocessing the gperf header file,
they might contain important bits without which compilation/preprocessing
might fail (e.g. with clang on Android). cc.cmd_array() does not include
the c_args and we can't easily look them up from the meson.build file, so
we have to retrieve from the introspection info.

This is basically the Meson equivalent to commit 57103773.
11 jobs for meson-gperf-preprocessing-crosscompilation-android in 5 minutes and 57 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #6702233
meson android arm64 fedora

00:01:35

passed #6702231
gst-macos-10.15
meson macos

00:03:00

passed #6702228
meson-mingw-w64-build

00:05:05

manual #6702232
docker windows 1809 allowed to fail manual
meson msys2
passed #6702226
meson-shared-build

00:03:25

passed #6702227
meson-static-build

00:03:26

passed #6702229
docker windows 1809
meson vs2017 amd64

00:01:21

passed #6702230
docker windows 1809
meson vs2017 x86

00:01:20

passed #6702225
mingw-build

00:05:52

passed #6702223
shared-build

00:04:53

passed #6702224
static-build

00:05:57