diff --git a/Makefile.in b/Makefile.in
index 8236bbd6b..ccfceda29 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -1,5 +1,5 @@
 # Extract the version string from nmap.h.
-export NMAP_VERSION := $(shell grep '^\#[ \t]*define[ \t]\+NMAP_VERSION' nmap.h | sed -e 's/.*"\(.*\)".*/\1/' -e 'q')
+export NMAP_VERSION := $(shell echo NMAP_VERSION | $(CPP) -imacros nmap.h - | sed -n '$$s/[" ]//g;$$p')
 NMAP_PLATFORM=@host@
 datarootdir = @datarootdir@
 prefix = @prefix@
diff --git a/macosx/Makefile b/macosx/Makefile
index 23caf6ada..506671cab 100644
--- a/macosx/Makefile
+++ b/macosx/Makefile
@@ -1,8 +1,8 @@
 # This makefile builds a disk image (.dmg) containing the installer for Nmap,
 # Zenmap, Ncat, and Ndiff.
 
-NMAP_VERSION := $(shell grep '^\#[ \t]*define[ \t]\+NMAP_VERSION' ../nmap.h | sed -e 's/.*"\(.*\)".*/\1/' -e 'q')
-NMAP_NUM_VERSION := $(shell grep '^\#[ \t]*define[ \t]\+NMAP_NUM_VERSION' ../nmap.h | sed -e 's/.*"\(.*\)".*/\1/' -e 'q')
+NMAP_VERSION := $(shell echo NMAP_VERSION | $(CPP) -imacros nmap.h - | sed -n '$$s/[" ]//g;$$p')
+NMAP_VERSION := $(shell echo NMAP_NUM_VERSION | $(CPP) -imacros nmap.h - | sed -n '$$s/[" ]//g;$$p')
 #OSX_VERSION=$(shell sw_vers -productVersion | cut -d'.' -f1,2 | tr -d ' ')
 OSX_VERSION=10.11
 OSX_MIN_VERSION = 10.9
diff --git a/mswin32/Makefile b/mswin32/Makefile
index 4a687a1b7..e5c8f5f5d 100644
--- a/mswin32/Makefile
+++ b/mswin32/Makefile
@@ -5,8 +5,8 @@ VCEXPRESS := $(shell reg query "HKEY_CLASSES_ROOT\\Applications\\devenv.exe\\she
 SIGNTOOL := $(shell reg query "HKEY_LOCAL_MACHINE\\SOFTWARE\\Wow6432Node\\Microsoft\\Microsoft SDKs\\Windows\\v8.1" /v "InstallationFolder" | egrep InstallationFolder | cut -d ' ' -f13- | sed 's%\\%/%g' | tr -d '\r\n' | sed 's%$$%bin/x86/signtool.exe%')
 NMAPDIR=..
 NMAPDIR_WIN=$(shell echo '$(NMAPDIR)' | sed 's|/cygdrive/\(.\)|\1:|;s|/|\\|g')
-export NMAP_VERSION := $(shell grep '^\#[ \t]*define[ \t]\+NMAP_VERSION' $(NMAPDIR)/nmap.h | sed -e 's/.*"\(.*\)".*/\1/' -e 'q')
-export NMAP_NUM_VERSION := $(shell grep '^\#[ \t]*define[ \t]\+NMAP_NUM_VERSION' $(NMAPDIR)/nmap.h | sed -e 's/.*"\(.*\)".*/\1/' -e 'q')
+export NMAP_VERSION := $(shell echo NMAP_VERSION | $(CPP) -imacros $(NMAPDIR)/nmap.h - | sed -n '$$s/[" ]//g;$$p')
+export NMAP_VERSION := $(shell echo NMAP_NUM_VERSION | $(CPP) -imacros $(NMAPDIR)/nmap.h - | sed -n '$$s/[" ]//g;$$p')
 export NPCAP_VERSION := $(shell ls npcap-*.exe | sed -e 's/npcap-\([0-9.]*\)[-oem]*\.exe/\1/' -e 'q')
 COMMA_VERSION=$(shell echo $(NMAP_NUM_VERSION) | tr '.' ',')
 LOGLOC=c:nmapbuild.log
diff --git a/nmap.h b/nmap.h
index 8e12fa6c6..549dbec0b 100644
--- a/nmap.h
+++ b/nmap.h
@@ -118,11 +118,20 @@
 #endif
 #define NMAP_URL "https://nmap.org"
 
+#define _STR(X) #X
+#define STR(X)  _STR(X)
+
 #ifndef NMAP_VERSION
 /* Edit this definition only within the quotes, because it is read from this
    file by the makefiles. */
-#define NMAP_VERSION "7.91SVN"
-#define NMAP_NUM_VERSION "7.91.1.0"
+#define NMAP_MAJOR 7
+#define NMAP_MINOR 91
+#define NMAP_BUILD 1
+/* SVN, BETA, etc. */
+#define NMAP_SPECIAL "SVN"
+
+#define NMAP_VERSION STR(NMAP_MAJOR) "." STR(NMAP_MINOR) NMAP_SPECIAL
+#define NMAP_NUM_VERSION STR(NMAP_MAJOR) "." STR(NMAP_MINOR) "." STR(NMAP_BUILD) ".0"
 #endif
 
 #define NMAP_XMLOUTPUTVERSION "1.05"
@@ -136,8 +145,6 @@
 #define MAX_TIMEOUTS MAX_SOCKETS   /* How many timed out connection attempts
                                       in a row before we decide the host is
                                       dead? */
-#define _STR(X) #X
-#define STR(X)  _STR(X)
 #define DEFAULT_TCP_PROBE_PORT 80 /* The ports TCP ping probes go to if
                                      unspecified by user -- uber hackers
                                      change this to 113 */