diff --git a/build.vars b/build.vars
index cc073f5..709635b 100644
--- a/build.vars
+++ b/build.vars
@@ -13,7 +13,7 @@
 : ${BUILD_STATUS_FINISHED_AT_CURRENT_FNAME:=${PREFIX}/BUILD_FINISHED_AT};
 : ${BUILD_STATUS_IN_PROGRESS_FNAME:=${PREFIX}/BUILD_IN_PROGRESS};
 : ${CFLAGS_DEFAULT:=-g2 -O0};
-: ${CHECK_PREREQ_CMDS:="aclocal autoconf autopoint bunzip2 flex git gunzip install libtool make makeinfo mktemp nl openssl patch sed sort tar tee tr sha256sum wget xz"};
+: ${CHECK_PREREQ_CMDS:="aclocal autoconf autopoint bunzip2 flex git groff gunzip install libtool make makeinfo mktemp nl nroff openssl patch sed sort tar tee tr sha256sum wget xz"};
 : ${CHECK_PREREQ_FILES:="/usr/include/gmpxx.h /usr/include/mpc.h /usr/include/mpfr.h"};
 : ${CHECK_PATH_VARS:="PREFIX PREFIX_NATIVE WORKDIR"};
 : ${CLEAR_ENV_VARS_EXCEPT:="HOME PATH SHELL TERM USER"};