Mine

check_lib X11/extensions/Xrandr.h XRRSelectInput -lXrandr
check_header X11/extensions/Xrandr.h
check_cpp
BEGIN /tmp/mythtv_conf.ANa3QIrs.c
    1   #include <X11/extensions/Xrandr.h>
    2   int x;
END /tmp/mythtv_conf.ANa3QIrs.c
gcc -D_ISOC99_SOURCE -D_POSIX_C_SOURCE=200112 -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_POSIX_C_SOURCE=200112 -D_XOPEN_SOURCE=600 -DPIC -std=c99 -DNDEBUG -fomit-frame-pointer -fPIC -pthread -g -Wall -Wdisabled-optimization -Wpointer-arith -Wwrite-strings -Wtype-limi$
/tmp/mythtv_conf.ANa3QIrs.c:1:35: fatal error: X11/extensions/Xrandr.h: No such file or directory
 #include <X11/extensions/Xrandr.h>
                                   ^
compilation terminated.