pgsql: ecpg: move some functions into a new file ecpg/preproc/util.c.

ecpg: move some functions into a new file ecpg/preproc/util.c.

mm_alloc and mm_strdup were in type.c, which seems a completely
random choice. No doubt the original author thought two small
functions didn't deserve their own file. But I'm about to add
some more memory-management stuff beside them, so let's put them
in a less surprising place. This seems like a better home for
mmerror, mmfatal, and the cat_str/make_str family, too.

Discussion: https://postgr.es/m/2011420.1713493114@sss.pgh.pa.us

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/f18231e817599246fc99a798c9bf57ab785db91f

Modified Files
--------------
src/interfaces/ecpg/preproc/Makefile | 1 +
src/interfaces/ecpg/preproc/ecpg.header | 129 ------------------
src/interfaces/ecpg/preproc/meson.build | 1 +
src/interfaces/ecpg/preproc/preproc_extern.h | 4 +
src/interfaces/ecpg/preproc/type.c | 24 ----
src/interfaces/ecpg/preproc/util.c | 189 +++++++++++++++++++++++++++
6 files changed, 195 insertions(+), 153 deletions(-)