Temporary header file '/tmp/PZcGS2TQAy/dump1.h' with the following content will be compiled to create GCC translation unit dump:

  // add defines
  #define __STDC_VERSION__ 201710L
#define _GXX_NULLPTR_T
#define CLUTTER_ENABLE_COMPOSITOR_API 1
#define _REGEX_NELTS(n)
#define _Atomic
#define PACKED
#define getaddrinfo_a(a,b,c,d)

  // add includes
  #include "/usr/include/mapserver/cgiutil.h"
  #include "/usr/include/mapserver/dejavu-sans-condensed.h"
  #include "/usr/include/mapserver/dxfcolor.h"
  #include "/usr/include/mapserver/fontcache.h"
  #include "/usr/include/mapserver/hittest.h"
  #include "/usr/include/mapserver/mapagg.h"
  #include "/usr/include/mapserver/mapaxisorder.h"
  #include "/usr/include/mapserver/mapcopy.h"
  #include "/usr/include/mapserver/mapentities.h"
  #include "/usr/include/mapserver/maperror.h"
  #include "/usr/include/mapserver/mapfile.h"
  #include "/usr/include/mapserver/mapflatgeobuf.h"
  #include "/usr/include/mapserver/mapgml.h"
  #include "/usr/include/mapserver/mapgraph.h"
  #include "/usr/include/mapserver/maphash.h"
  #include "/usr/include/mapserver/maphttp.h"
  #include "/usr/include/mapserver/mapiconv.h"
  #include "/usr/include/mapserver/mapio.h"
  #include "/usr/include/mapserver/mapkmlrenderer.h"
  #include "/usr/include/mapserver/maplibxml2.h"
  #include "/usr/include/mapserver/mapogcapi.h"
  #include "/usr/include/mapserver/mapogcfilter.h"
  #include "/usr/include/mapserver/mapogcsld.h"
  #include "/usr/include/mapserver/mapoglcontext.h"
  #include "/usr/include/mapserver/mapoglrenderer.h"
  #include "/usr/include/mapserver/mapows.h"
  #include "/usr/include/mapserver/mapowscommon.h"
  #include "/usr/include/mapserver/mapparser.h"
  #include "/usr/include/mapserver/mappostgis.h"
  #include "/usr/include/mapserver/mapprimitive.h"
  #include "/usr/include/mapserver/mapproject.h"
  #include "/usr/include/mapserver/mapraster.h"
  #include "/usr/include/mapserver/mapregex.h"
  #include "/usr/include/mapserver/mapresample.h"
  #include "/usr/include/mapserver/mapserv-config.h"
  #include "/usr/include/mapserver/mapserv.h"
  #include "/usr/include/mapserver/mapserver-api.h"
  #include "/usr/include/mapserver/mapserver-config.h"
  #include "/usr/include/mapserver/mapserver-version.h"
  #include "/usr/include/mapserver/mapserver.h"
  #include "/usr/include/mapserver/mapshape.h"
  #include "/usr/include/mapserver/mapsymbol.h"
  #include "/usr/include/mapserver/maptemplate.h"
  #include "/usr/include/mapserver/mapthread.h"
  #include "/usr/include/mapserver/maptile.h"
  #include "/usr/include/mapserver/maptime.h"
  #include "/usr/include/mapserver/maptree.h"
  #include "/usr/include/mapserver/maputfgrid.h"
  #include "/usr/include/mapserver/mapwcs.h"
  #include "/usr/include/mapserver/uthash.h"

The GCC parameters:
  gcc -fdump-lang-raw -fkeep-inline-functions -c -x c++ -fpermissive -w "/tmp/PZcGS2TQAy/dump1.h"

In file included from /usr/include/mapserver/mapshape.h:35,
                 from /usr/include/mapserver/mapserver.h:126,
                 from /usr/include/mapserver/fontcache.h:1,
                 from /tmp/PZcGS2TQAy/dump1.h:15:
/usr/include/mapserver/mapproject.h:46:12: fatal error: proj_api.h: No such file or directory
   46 | #  include <proj_api.h>
      |            ^~~~~~~~~~~~
compilation terminated.