diff --git a/doc/Guidebook.mn b/doc/Guidebook.mn
index a8f739d5a..89f581285 100644
--- a/doc/Guidebook.mn
+++ b/doc/Guidebook.mn
@@ -31,8 +31,21 @@
 .lt 70n
 .\}
 .
-.so tmac.nh \" extra macros which aren't in tmac.n
-.if !\n(nH .so doc/tmac.nh
+.\" Load extra macros that "tmac.n" doesn't define.
+.de So
+.ie \n(.g&(\n(.x=1)&(\n(.y>22) .soquiet \\$1
+.el                            .so      \\$1
+..
+.
+.So tmac.nh
+.if !\n(nH So doc/tmac.nh
+.
+.if !\n(nH \{\
+.tm fatal error: cannot locate "tmac.nh" macro package
+.ab
+.\}
+.
+.rm So
 .
 .\" building Guidebook.txt doesn't have CR font available; groff 1.23 issues
 .\" a warning each time any font can't be loaded; earlier versions silently
diff --git a/doc/makedefs.6 b/doc/makedefs.6
index 136084473..5e24242fa 100644
--- a/doc/makedefs.6
+++ b/doc/makedefs.6
@@ -99,7 +99,7 @@ only if it is present, to obtain
 .B githash=
 and 
 .B gitbranch=
- info and include related preprocessor #defines in
+info and include related preprocessor #defines in
 .I date.h
 file.
 .br
diff --git a/doc/tmac.nh b/doc/tmac.nh
index 86bc643b4..f8c30c2d0 100644
--- a/doc/tmac.nh
+++ b/doc/tmac.nh
@@ -29,7 +29,7 @@
 .\" labeled paragraph label (and first line)
 .de PL
 .br
-\\h'|-\\n(PYu'\\$1\\h'|-\\n(PXu'\ -\ \\c \" back up, output the label, then
+\\h'|-\\n(PYu'\\$1\\h'|-\\n(PXu'\ -\ \\c\" back up, output the label, then
 .					\" skip to width-of(" - ") before the
 .					\" normal indentation, output the " - "
 .					\" then attach the next line (the
diff --git a/sys/unix/hints/include/misc.370 b/sys/unix/hints/include/misc.370
index 6608cf45a..7f57697b4 100644
--- a/sys/unix/hints/include/misc.370
+++ b/sys/unix/hints/include/misc.370
@@ -70,34 +70,38 @@ NROFF = mandoc
 MAN2TXTPRE = -T ascii
 MAN2TXTPOST= | col -b
 else
-#detection of groff
-NROFFISGROFF := $(shell echo `nroff --version | grep "GNU groff version"`)
+#
+# Detect groff.
+NROFFISGROFF := $(shell echo `nroff --version | grep -c 'GNU.*groff.*version'`)
 #$(info NROFFISGROFF=$(NROFFISGROFF))
-ifneq "$(NROFFISGROFF)" ""
-# get the version of groff and flag if it is gt or eq to 1.23
-GROFFGE123 := $(shell expr `echo $(NROFFISGROFF) | cut -f2 -d.` \>= 23)
-# or less than 1.24
-GROFFLT124 := $(shell expr `echo $(NROFFISGROFF) | cut -f2 -d.` \< 24)
-# -Wtab -Wrange are for the sake of tmac.n.
-NROFF_FLAGS := -wall -Wtab -Wrange
-ifneq "$(GROFFLT124)" ""
-NROFF_FLAGS += -Wel -Wscale
-endif
-endif  # NROFFISGROFF
+ifneq "$(NROFFISGROFF)" "0"
+# Gather groff's minor version number (register `.y`).
+GROFFMINORVERSION := $(shell printf '.tm \\n[.y]\n' | nroff 2>&1)
+#$(info GROFFMINORVERSION=$(GROFFMINORVERSION))
+# Silence warnings produced by tmac.n, which NetHack does not modify.
+NROFF_FLAGS := -wall -Wrange -Wscale -Wtab
+# groff <= 1.23 also supported an "el" warning category that was buggy.
+GROFFLE123 := $(shell expr $(GROFFMINORVERSION) \<= 23)
+#$(info GROFFLE123=$(GROFFLE123))
+ifeq "$(GROFFLE123)" "1"
+NROFF_FLAGS += -Wel
+endif  # end groff less than 1.23
+endif  # end NROFFISGROFF
+# $(info NROFF_FLAGS=$(NROFF_FLAGS))
 
 ifneq "$(NROFFISGROFF)" ""   # It's groff
 # add the -Tascii flag used by groff
 MAN2TXTPRE += -Tascii
-ifneq "$(GROFFGE123)" ""   # It's groff 1.23 or greater
-#$(info GROFFGE123=$(GROFFGE123))
 # nroff in groff 1.23 supports the -P option to pass arguments to the
 # output driver.  -cbou are flags to grotty(1).
+GROFFGE123 := $(shell expr $(GROFFMINORVERSION) \>= 23)
+#$(info GROFFGE123=$(GROFFGE123))
+ifeq "$(GROFFGE123)" "1"
 MAN2TXTPRE += -P -cbou
 MAN2TXTPOST=
 else
 MAN2TXTPRE += -c
-# groff less than 1.23
-endif
+endif  # end groff less than 1.23
 endif  # end groff-specific
 endif  # not USE_MANDOC