ifile won't compile

When I tried to compile ifile, I got the following error:

$ gmake install
gcc -c   -I. -I./include -I./argp -DPACKAGE_NAME=\"\" 
-DPACKAGE_TARNAME=\"\" -DP
ACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" 
-DHAVE_STRCHR
=1 -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 
-DHAVE_STDLIB_H=1 -
DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_UNISTD_H=1  
-g -O2
-Wall -Wimplicit -o opts.o opts.c
In file included from ./include/ifile.h:33,
                 from opts.c:21:
./argp/argp.h:395: warning: `extern' is not at beginning of declaration
opts.c: In function `parse_opt':
opts.c:249: parse error before `/'
gmake: *** [opts.o] Error 1


What's wrong???