When trying to compile DBD-Firebird on openSUSE 12.2, following error occurs even though the appropriate -devel packages are installed:

cc -c  -I"/usr/include" -I"/usr/lib/perl5/vendor_perl/5.16.0/x86_64-linux-thread-multi/auto/DBI" -D_REENTRANT -D_GNU_SOURCE -DPERL_USE_SAFE_PUTENV -fno-strict-aliasing -pipe -fstack-protector -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -fmessage-length=0 -O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables -fasynchronous-unwind-tables -g -Wall -pipe   -DVERSION=\"1.11\" -DXS_VERSION=\"1.11\" -fPIC "-I/usr/lib/perl5/5.16.0/x86_64-linux-thread-multi/CORE"  -DEMBEDDED FirebirdEmbedded.c
In file included from FirebirdEmbedded.h:18:0,
                 from FirebirdEmbedded.xs:20:
dbdimp.h:80:23: fatal error: ibase.h: No such file or directory
compilation terminated.

Setting:

export C_INCLUDE_PATH=/usr/include/firebird

will ensure the correct include path for ibase.h is found.