LIBM (from --with-libm=...); this actually broke the customizability
offered by the latter option. Thanks go to Clay Spence for reporting
this.
# checks for libraries
AC_CHECK_LIB(dl, dlopen) # Dynamic linking for SunOS/Solaris and SYSV
AC_CHECK_LIB(dld, shl_load) # Dynamic linking for HP-UX
-AC_CHECK_LIB(m, pow) # Std math lib -- assume needed if it exists
# Most SVR4 platforms (e.g. Solaris) need -lsocket and -lnsl.
# However on SGI IRIX, these exist but are broken.
# BeOS' sockets are stashed in libnet.