On the first make, it built normally.  I then changed my mind
about the configuration, went back and did "make clean" followed by 
another "make".  Got this:

bison -p php -v -d ./language-parser.y -o language-parser.tab.c
gcc -O2   -I. -I.   -I/usr/local/src/apache_1.2.6/src      
	-I/usr/include/mysql   -I/usr/local/pgsql/include        
	-c language-parser.tab.c -o language-parser.tab.o
/usr/lib/bison.simple: In function `phpparse':
/usr/lib/bison.simple:558: `yytname' undeclared (first use this function)
/usr/lib/bison.simple:558: (Each undeclared identifier is reported only once
/usr/lib/bison.simple:558: for each function it appears in.)

It does not run bison on the first make, as there is already
an up-to-date "language-parser.tab.c" in the source directory.
I'm guessing that there's an option missing from the bison
invocation or else there's some kind of version problem.  Bison --version
gives this:

GNU Bison version 1.24