The lang/moscow_ml port doesn't build on 5.0-p2:

$ make
...
cd intinf; make INCDIR=../../runtime
gcc -Dunix -O2 -fno-defer-pop -fPIC -I../../runtime -c -o intinf.o intinf.c
intinf.c:4:17: gmp.h: No such file or directory
intinf.c: In function `largeint_finalize':
intinf.c:85: `MP_INT' undeclared (first use in this function)
intinf.c:85: (Each undeclared identifier is reported only once
intinf.c:85: for each function it appears in.)
intinf.c:85: `mpint' undeclared (first use in this function)
intinf.c:85: syntax error before ')' token
intinf.c: In function `largeint_alloc':
intinf.c:157: `MP_INT' undeclared (first use in this function)
intinf.c: In function `largeint_make':
intinf.c:175: `MP_INT' undeclared (first use in this function)
intinf.c:175: syntax error before ')' token
intinf.c: In function `largeint_make_si':
intinf.c:182: `MP_INT' undeclared (first use in this function)
intinf.c:182: syntax error before ')' token
intinf.c: In function `largeint_set':
intinf.c:188: `MP_INT' undeclared (first use in this function)
intinf.c:188: syntax error before ')' token
intinf.c:188: syntax error before ')' token
intinf.c: In function `largeint_set_si':
intinf.c:194: `MP_INT' undeclared (first use in this function)
intinf.c:194: syntax error before ')' token
intinf.c: In function `largeint_to_si':
intinf.c:200: `MP_INT' undeclared (first use in this function)
intinf.c:200: syntax error before ')' token
intinf.c: In function `largeint_neg':
intinf.c:209: `MP_INT' undeclared (first use in this function)
intinf.c:209: syntax error before ')' token
intinf.c:209: syntax error before ')' token
intinf.c: In function `largeint_add':
intinf.c:215: `MP_INT' undeclared (first use in this function)
intinf.c:215: syntax error before ')' token
intinf.c:215: syntax error before ')' token
intinf.c:215: syntax error before ')' token
intinf.c: In function `largeint_sub':
intinf.c:221: `MP_INT' undeclared (first use in this function)
intinf.c:221: syntax error before ')' token
intinf.c:221: syntax error before ')' token
intinf.c:221: syntax error before ')' token
intinf.c: In function `largeint_mul':
intinf.c:227: `MP_INT' undeclared (first use in this function)
intinf.c:227: syntax error before ')' token
intinf.c:227: syntax error before ')' token
intinf.c:227: syntax error before ')' token
intinf.c: In function `largeint_tdiv':
intinf.c:234: `MP_INT' undeclared (first use in this function)
intinf.c:234: syntax error before ')' token
intinf.c:234: syntax error before ')' token
intinf.c:234: syntax error before ')' token
intinf.c: In function `largeint_tmod':
intinf.c:240: `MP_INT' undeclared (first use in this function)
intinf.c:240: syntax error before ')' token
intinf.c:240: syntax error before ')' token
intinf.c:240: syntax error before ')' token
intinf.c: In function `largeint_tdivmod':
intinf.c:246: `MP_INT' undeclared (first use in this function)
intinf.c:246: syntax error before ')' token
intinf.c:246: syntax error before ')' token
intinf.c:247: syntax error before ')' token
intinf.c:247: syntax error before ')' token
intinf.c: In function `largeint_fdiv':
intinf.c:254: `MP_INT' undeclared (first use in this function)
intinf.c:254: syntax error before ')' token
intinf.c:254: syntax error before ')' token
intinf.c:254: syntax error before ')' token
intinf.c: In function `largeint_fmod':
intinf.c:260: `MP_INT' undeclared (first use in this function)
intinf.c:260: syntax error before ')' token
intinf.c:260: syntax error before ')' token
intinf.c:260: syntax error before ')' token
intinf.c: In function `largeint_fdivmod':
intinf.c:266: `MP_INT' undeclared (first use in this function)
intinf.c:266: syntax error before ')' token
intinf.c:266: syntax error before ')' token
intinf.c:267: syntax error before ')' token
intinf.c:267: syntax error before ')' token
intinf.c: In function `largeint_cmp':
intinf.c:273: `MP_INT' undeclared (first use in this function)
intinf.c:273: syntax error before ')' token
intinf.c:273: syntax error before ')' token
intinf.c: In function `largeint_cmp_si':
intinf.c:284: `MP_INT' undeclared (first use in this function)
intinf.c:284: syntax error before ')' token
intinf.c: In function `largeint_sizeinbase':
intinf.c:294: `MP_INT' undeclared (first use in this function)
intinf.c:294: syntax error before ')' token
intinf.c: In function `largeint_set_str':
intinf.c:308: `MP_INT' undeclared (first use in this function)
intinf.c:308: syntax error before ')' token
intinf.c: In function `largeint_get_str':
intinf.c:318: `MP_INT' undeclared (first use in this function)
intinf.c:318: syntax error before ')' token
intinf.c:321: syntax error before ')' token
intinf.c: In function `largeint_pow_ui':
intinf.c:334: `MP_INT' undeclared (first use in this function)
intinf.c:334: syntax error before ')' token
intinf.c:334: syntax error before ')' token
*** Error code 1

Stop in /usr/ports/lang/moscow_ml/work/mosml/src/dynlibs/intinf.
*** Error code 1

Stop in /usr/ports/lang/moscow_ml/work/mosml/src/dynlibs.
*** Error code 1

Stop in /usr/ports/lang/moscow_ml/work/mosml/src.
*** Error code 1

Stop in /usr/ports/lang/moscow_ml.

How-To-Repeat: 
Try to build lang/moscow_ml on 5.0/i386.