Checking if your kit is complete...
Looks good
Note (probably harmless): No library found for -lsql4
Writing Makefile for DBD::Informix4
cp Informix4.pm blib/lib/DBD/Informix4.pm
/Users/cpanrun/pristine/5.8.7/bin/perl /Users/cpanrun/pristine/5.8.7/lib/5.8.7/ExtUtils/xsubpp  -typemap /Users/cpanrun/pristine/5.8.7/lib/5.8.7/ExtUtils/typemap  Informix4.xs > Informix4.xsc && mv Informix4.xsc Informix4.c
gcc -c  -I/incl -I/Users/cpanrun/pristine/5.8.7/lib/5.8.7/darwin-thread-multi-2level/DBI -I/Users/cpanrun/pristine/5.8.7/lib/site_perl/5.8.7/darwin-thread-multi-2level/auto/DBI -fno-common -DPERL_DARWIN -no-cpp-precomp -arch ppc -arch i386 -nostdinc -B/Developer/SDKs/MacOSX10.4u.sdk/usr/include/gcc -B/Developer/SDKs/MacOSX10.4u.sdk/usr/lib/gcc -isystem/Developer/SDKs/MacOSX10.4u.sdk/usr/include -F/Developer/SDKs/MacOSX10.4u.sdk/System/Library/Frameworks -mmacosx-version-min=10.3 -DUSE_SITECUSTOMIZE -DNO_HASH_SEED -fno-strict-aliasing -pipe -O3   -DVERSION=\"0.23\" -DXS_VERSION=\"0.23\"  "-I/Users/cpanrun/pristine/5.8.7/lib/5.8.7/darwin-thread-multi-2level/CORE"   Informix4.c
In file included from Informix4.h:13,
                 from Informix4.xs:9:
dbdimp.h:13:19: error: sqlca.h: No such file or directory
In file included from Informix4.h:13,
                 from Informix4.xs:9:
dbdimp.h:13:19: error: dbdimp.h:14:19: sqlca.h: No such file or directoryerror: 
sqlda.h: No such file or directory
dbdimp.h:14:19: dbdimp.h:15:20:error:  sqlda.h: No such file or directoryerror: 
sqlhdr.h: No such file or directory
dbdimp.h:15:20: dbdimp.h:16:20:error:  sqlhdr.h: No such file or directoryerror: 
values.h: No such file or directory
dbdimp.h:16:20: error: values.h: No such file or directoryIn file included from Informix4.h:13,
                 from Informix4.xs:9:
dbdimp.h:18: error: parse error before '*' token

In file included from Informix4.h:13,
                 from Informix4.xs:9:
dbdimp.h:18: error: parse error before '*' token
lipo: can't open input file: /var/tmp//ccG1fjlL.out (No such file or directory)
make: *** [Informix4.o] Error 1