Build error when building version of mozilla-central fetched 7th June 2019

build_error

./mach build
 0:00.72 Clobber not needed.
 0:00.72 Adding make options from /Users/emilytoop/Development/FirefoxDeskop/gecko/mozconfig
    MOZ_OBJDIR=/Users/emilytoop/Development/FirefoxDeskop/gecko/obj-i686-unknown-linux-android
    OBJDIR=/Users/emilytoop/Development/FirefoxDeskop/gecko/obj-i686-unknown-linux-android
    FOUND_MOZCONFIG=/Users/emilytoop/Development/FirefoxDeskop/gecko/mozconfig
    export FOUND_MOZCONFIG
 0:00.74 /usr/bin/make -f client.mk -s
 0:01.06 Elapsed: 0.00s; From dist/public: Kept 0 existing; Added/updated 0; Removed 0 files and 0 directories.
 0:01.06 Elapsed: 0.00s; From dist/private: Kept 0 existing; Added/updated 0; Removed 0 files and 0 directories.
 0:01.07 Elapsed: 0.01s; From dist/xpi-stage: Kept 0 existing; Added/updated 62; Removed 0 files and 0 directories.
 0:01.27 Elapsed: 0.21s; From dist/bin: Kept 15 existing; Added/updated 964; Removed 0 files and 0 directories.
 0:01.41 Elapsed: 0.35s; From _tests: Kept 30 existing; Added/updated 1122; Removed 0 files and 0 directories.
 0:01.78 Elapsed: 0.73s; From dist/include: Kept 1594 existing; Added/updated 4096; Removed 0 files and 0 directories.
 0:01.81 ./mozilla-config.h.stub
 0:01.81 ./buildid.h.stub
 0:01.81 ./source-repo.h.stub
 0:02.08 config
 0:02.11 /Users/emilytoop/Development/FirefoxDeskop/gecko/config/pathsub.c/Users/emilytoop/Development/FirefoxDeskop/gecko/config/nsinstall.c::10:10: fatal error: 'assert.h' file not found
 0:02.11 10:10: fatal error: 'stdio.h' file not found
 0:02.11 #include <assert.h>
 0:02.11          ^~~~~~~~~~
 0:02.11 #include <stdio.h> /* OSF/1 requires this before grp.h, so put it first */
 0:02.11          ^~~~~~~~~
 0:02.11 1 error generated.
 0:02.11 1 error generated.
 0:02.11 make[4]: *** [host_pathsub.o] Error 1
 0:02.11 make[4]: *** Waiting for unfinished jobs....
 0:02.11 make[4]: *** [host_nsinstall.o] Error 1
 0:02.11 make[3]: *** [config/host] Error 2
 0:02.11 make[2]: *** [export] Error 2
 0:02.11 make[1]: *** [default] Error 2
 0:02.11 make: *** [build] Error 2
 0:02.13 0 compiler warnings present.