pkg-config incompletely called in configure

[dmacks]

On OS X 10.13 libgeotiff-1.6.0:

./configure --prefix=/sw --with-zip=/usr/include --with-jpeg=/sw --with-libtiff=/sw --disable-doxygen-doc
[...]
checking for PROJ >= 6 library... checking for PROJ... no
checking for proj_create_from_wkt in -lproj... yes
checking proj.h usability... yes
checking proj.h presence... yes
checking for proj.h... yes
configure: proj.h found

But I do have proj.pc and pkg-config can find it normally. Instead, there's a flaw in how PKG_CHECK_MODULES is being called. There are several previous PKG_CHECK_MODULES that are not being called due to the --with-* for their libs. So this is the first P_C_M that is called but not the first in the ./configure script. As a result, some initialization that the autotools do for "the first P_C_M in configure.ac" are not run. It's exactly the bug described at https://autotools.io/pkgconfig/pkg_check_modules.html section 3.4, and the fix described there works for me.

Adding

PKG_PROG_PKG_CONFIG0

to the "Checks for programs" block gives me:

checking for PROJ >= 6 library... checking for proj... yes
checking proj.h usability... yes
checking proj.h presence... yes
checking for proj.h... yes
configure: proj.h found