diff --git a/Makefile.macosx b/Makefile.macosx
index b6330da..55d3106 100644
--- a/Makefile.macosx
+++ b/Makefile.macosx
@@ -1,5 +1,5 @@
 #
-# Makefile for Macintosh 10.8+ version of Dire Wolf.
+# Makefile for Macintosh 10.6+ version of Dire Wolf.
 #
 
 # TODO: This is a modified version of Makefile.linux and it
@@ -9,6 +9,20 @@
 # Maybe the most of the differences could go in to platform specific include
 # files rather than cluttering it up with too many if blocks.
 
+# Changes:
+#
+# 16 Dec 2015
+# 1. Added condition check for gps/gpsd code. Commented out due to 32/64 bit
+#    library issues. Macports gpsd build problem.
+# 2. SDK version checks are now performed by a bash script 'search_sdks.sh'.
+#    This should resolve the varied locations Apple stored the SDKs on the different
+#    Xcode/OS versions. Executing 'make' on the first pass asks the operator
+#    which SDK he/she wishes to use. Executing 'make clean' resets the SDK
+#    selection and operator intervention is once again required. Selected SDK
+#    information resides in a file named './use_this_sdk' in the current working
+#    directory.
+# 3. Removed fsk_fast_filter.h from atest receipe, clang compiler was having
+#    a hissy fit. Not check with GCC.
 
 all : direwolf decode_aprs text2tt tt2text ll2utm utm2ll aclients atest log2gpx gen_packets ttcalc direwolf.conf
 	@echo " "
@@ -16,34 +30,33 @@ all : direwolf decode_aprs text2tt tt2text ll2utm utm2ll aclients atest log2gpx
 	@echo " "
 	@echo "      sudo make install"
 	@echo " "
-	@echo "System SDK's (10.8 - 10.10) must be located here to make use of them. "
-	@echo "     /Developer/SDKs "
 	@echo " "
 
 SYS_LIBS :=
 SYS_MIN :=
-SDK := $(shell find /Developer -maxdepth 1 -type d -name "SDKs")
+#SDK := $(shell find /Developer -maxdepth 1 -type d -name "SDKs")
 #$(info $$SDK = ${SDK})
-ifeq (${SDK},/Developer/SDKs)
-	SDK := $(shell find /Developer/SDKs -maxdepth 1 -type d -name "MacOSX10.8.sdk")
-	ifeq (${SDK},/Developer/SDKs/MacOSX10.8.sdk)
-		SYS_LIBS := -isystem /Developer/SDKs/MacOSX10.8.sdk
-		SYS_MIN := -mmacosx-version-min=10.8
-	else
-		SDK := $(shell find /Developer/SDKs -maxdepth 1 -type d -name "MacOSX10.9.sdk")
-		ifeq (${SDK},/Developer/SDKs/MacOSX10.9.sdk)
-			SYS_LIBS := -isystem /Developer/SDKs/MacOSX10.9.sdk
-			SYS_MIN := -mmacosx-version-min=10.9
-		else
-			SDK := $(shell find /Developer/SDKs -maxdepth 1 -type d -name "MacOSX10.10.sdk")
-			ifeq (${SDK},/Developer/SDKs/MacOSX10.10.sdk)
-				SYS_LIBS := -isystem /Developer/SDKs/MacOSX10.10.sdk
-				SYS_MIN := -mmacosx-version-min=10.10
-			endif
-		endif
-	endif
-endif
+#ifeq (${SDK},/Developer/SDKs)
+#	SDK := $(shell find /Developer/SDKs -maxdepth 1 -type d -name "MacOSX10.8.sdk")
+#	ifeq (${SDK},/Developer/SDKs/MacOSX10.8.sdk)
+#		SYS_LIBS := -isystem /Developer/SDKs/MacOSX10.8.sdk
+#		SYS_MIN := -mmacosx-version-min=10.8
+#	else
+#		SDK := $(shell find /Developer/SDKs -maxdepth 1 -type d -name "MacOSX10.9.sdk")
+#		ifeq (${SDK},/Developer/SDKs/MacOSX10.9.sdk)
+#			SYS_LIBS := -isystem /Developer/SDKs/MacOSX10.9.sdk
+#			SYS_MIN := -mmacosx-version-min=10.9
+#		else
+#			SDK := $(shell find /Developer/SDKs -maxdepth 1 -type d -name "MacOSX10.10.sdk")
+#			ifeq (${SDK},/Developer/SDKs/MacOSX10.10.sdk)
+#				SYS_LIBS := -isystem /Developer/SDKs/MacOSX10.10.sdk
+#				SYS_MIN := -mmacosx-version-min=10.10
+#			endif
+#		endif
+#	endif
+#endif
 
+SYS_LIBS := $(shell ./search_sdks.sh)
 EXTRA_CFLAGS :=
 DARWIN_CC := $(shell which clang)
 ifeq (${DARWIN_CC},)
@@ -184,11 +197,20 @@ LDLIBS += -framework Foundation -framework CoreServices
 CFLAGS += -DUSE_PORTAUDIO -I/opt/local/include
 
 # Uncomment following lines to enable GPS interface & tracker function.
-# Not available for MacOSX.
-# Although MacPorts has gpsd, wonder if it's the same thing.
+# Not available for MacOSX (as far as I know).
+# Although MacPorts has gpsd, wonder if it's the same thing. Add the check
+# just in case it works.
+# Well never mind, issue with Macports with 64bit libs ;-( leave the check in
+# until (if ever) Macports fixes the issue.
 
+#GPS_HEADER := $(shell find /opt/local/include -maxdepth 1 -type f -name "gps.h")
+#ifeq (${GPS_HEADER},)
+#GPS_OBJS :=
+#else
 #CFLAGS += -DENABLE_GPSD
-#LDLIBS += -lgps
+#LDLIBS += -L/opt/local/lib -lgps -lgpsd
+#GPS_OBJS := dwgps.o dwgpsnmea.o dwgpsd.o
+#endif
 
 # Name of current directory.
 # Used to generate zip file name for distribution.
@@ -206,7 +228,7 @@ direwolf : direwolf.o aprs_tt.o audio_portaudio.o audio_stats.o ax25_pad.o beaco
 		kiss.o kissnet.o latlong.o latlong.o log.o morse.o multi_modem.o \
 		nmea.o serial_port.o pfilter.o ptt.o rdq.o recv.o redecode.o rrbb.o server.o \
 		symbols.o telemetry.o textcolor.o tq.o tt_text.o tt_user.o xmit.o \
-		dwgps.o dwgpsnmea.o dwgpsd.o
+		dwgps.o dwgpsnmea.o
 	$(CC) $(CFLAGS) -o $@ $^ -lpthread $(LDLIBS) -lm
 
 
@@ -221,8 +243,6 @@ fsk_fast_filter.h : demod_afsk.c
 	$(CC) $(CFLAGS) -o gen_fff -DGEN_FFF demod_afsk.c dsp.c textcolor.c -lm
 	./gen_fff > fsk_fast_filter.h
 
-
-
 # UTM, USNG, MGRS conversions.
 
 geotranz.a : error_string.o  mgrs.o  polarst.o  tranmerc.o  ups.o  usng.o  utm.o
@@ -423,17 +443,19 @@ demod_afsk.o : tune.h
 demod_9600.o : tune.h
 
 testagc : atest.c demod.c dsp.c demod_afsk.c demod_9600.c hdlc_rec.c hdlc_rec2.o multi_modem.o rrbb.o \
-		fcs_calc.c ax25_pad.c decode_aprs.c telemetry.c latlong.c symbols.c tune.h textcolor.c
+        fcs_calc.c ax25_pad.c decode_aprs.c telemetry.c latlong.c symbols.c tune.h textcolor.c
 	$(CC) $(CFLAGS) -o atest $^ -lm
 	./atest 02_Track_2.wav | grep "packets decoded in" > atest.out
 
 
 # Unit test for AFSK demodulator
 
-
-atest : atest.c fsk_fast_filter.h demod.c dsp.c demod_afsk.c demod_9600.c hdlc_rec.c hdlc_rec2.o multi_modem.o rrbb.o \
-		fcs_calc.c ax25_pad.c decode_aprs.c dwgpsnmea.o dwgps.o serial_port.o telemetry.c latlong.c symbols.c textcolor.c tt_text.c
+atest : atest.c demod.c dsp.c demod_afsk.c demod_9600.c hdlc_rec.c hdlc_rec2.o multi_modem.o rrbb.o \
+        fcs_calc.c ax25_pad.c decode_aprs.c dwgpsnmea.o dwgps.o serial_port.o telemetry.c latlong.c symbols.c textcolor.c tt_text.c
 	$(CC) $(CFLAGS) -o $@ $^ -lm
+#atest : atest.c fsk_fast_filter.h demod.c dsp.c demod_afsk.c demod_9600.c hdlc_rec.c hdlc_rec2.o multi_modem.o rrbb.o \
+#        fcs_calc.c ax25_pad.c decode_aprs.c dwgpsnmea.o dwgps.o serial_port.o telemetry.c latlong.c symbols.c textcolor.c tt_text.c
+#	$(CC) $(CFLAGS) -o $@ $^ -lm
 
 # Unit test for inner digipeater algorithm
 
@@ -492,7 +514,7 @@ depend : $(wildcard *.c)
 .PHONY: clean
 clean :
 	rm -f direwolf decode_aprs text2tt tt2text ll2utm utm2ll aclients atest log2gpx gen_packets ttcalc \
-		fsk_fast_filter.h *.o *.a
+		fsk_fast_filter.h *.o *.a use_this_sdk
 	echo " " > tune.h
 
 
diff --git a/dwgpsd.c b/dwgpsd.c
index d970a88..5fc97bf 100644
--- a/dwgpsd.c
+++ b/dwgpsd.c
@@ -116,7 +116,7 @@ static struct gps_data_t gpsdata;
  * actually need the data and we don't have a lot of extra unnecessary
  * busy work going on.
  *
- * The current version of gpsd, supplied with Raspian, is 3.6 from back in 
+ * The current version of gpsd, supplied with Raspian (Wheezy), is 3.6 from back in 
  * May 2012, is missing support for the shared memory interface.  
  * 
  * I tried to download a newer source and build with shared memory support
@@ -132,6 +132,11 @@ static struct gps_data_t gpsdata;
  * 	sudo scons udev-install
  * 
  * For now, we will use the socket interface.  Maybe get back to this again someday.
+ *
+ * Update:  January 2016.
+ *
+ *	I'm told that it might work in Raspian, Jessie version.
+ *	Haven't tried it yet.
  */
 
 
diff --git a/man1/gen_packets.1 b/man1/gen_packets.1
index b07e7f6..f1782aa 100644
--- a/man1/gen_packets.1
+++ b/man1/gen_packets.1
@@ -98,10 +98,14 @@ Both of these are equivalent.  "-B 9600" automatically selects scrambled baseban
 Both of these generate 200 Hz shift, 300 baud, suitable for HF SSB transceiver.
 .RE
 .P
-.B echo -n "WB2OSZ>WORLD:Hello, world!" | gen_packets -a 25 -o x.wav -
+.B echo -n 'WB2OSZ>WORLD:Hello, world!' | gen_packets -a 25 -o x.wav -
+.PD 0
+.P
+.PD
+.B atest x.wav
 .P
 .RS
-Read message from stdin and put quarter volume sound into the file x.wav.
+Read message from stdin and put quarter volume sound into the file x.wav.  Decode the sound file.
 .RE
 .P
 
diff --git a/search_sdks.sh b/search_sdks.sh
new file mode 100644
index 0000000..3ddac3a
--- /dev/null
+++ b/search_sdks.sh
@@ -0,0 +1,109 @@
+#!/bin/bash
+#
+# This file is part of Dire Wolf, an amateur radio packet TNC.
+#
+# Bash script to search for SDKs on various MacOSX versions.
+#
+# Copyright (C) 2015 Robert Stiles
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+FILENAME="./use_this_sdk"
+selected_sdk=""
+valid_flag=0
+system_sdk=""
+
+if [ -f $FILENAME ]; then
+    selected_sdk=`cat $FILENAME`
+    if [ -d $selected_sdk ]; then
+        valid_flag=1
+    fi
+fi
+
+if [ $valid_flag -eq "0" ]; then
+    echo " " >&2
+    echo " " >&2
+    echo "Searching for SDKs.... (Wait for results)" >&2
+    echo " " >&2
+    echo "Enter the number and press Enter/Return Key" >&2
+    echo " " >&2
+    echo " " >&2
+
+    prompt="Select SDK to use:"
+
+    loc1=( $(find /Applications/XCode.app -type d -name "MacOSX10.*.sdk") )
+    loc2=( $(find /Developer/SDKs -maxdepth 1 -type d -name "MacOSX10.*.sdk") )
+
+    options=("${loc1[@]}" "${loc2[@]}")
+
+    if [ "${#options[@]}" -lt "2" ]; then
+        echo "$options"
+    fi
+
+    PS3="$prompt "
+    select opt in "${options[@]}" "Do not use any SDK" ; do
+        if (( REPLY == 1 + ${#options[@]} )) ; then
+            echo " "
+            break
+        elif (( REPLY > 0 && REPLY <= ${#options[@]} )) ; then
+            selected_sdk="$opt"
+            break
+        fi
+    done
+
+    if [ ! -z "$selected_sdk" ]; then
+        echo "$selected_sdk" > $FILENAME
+    else
+        echo " " > $FILENAME
+    fi
+fi
+
+if [ ! -z "$selected_sdk" ]; then
+    temp_str="$selected_sdk"
+    min_str=""
+    flag=true
+
+    # Search for the last MacOSX in the string.
+    while [ "${#temp_str}" -gt 4 ]; do
+        temp_str="${temp_str#*MacOSX}"
+        temp_str="${temp_str%%.sdk}"
+        min_str="$temp_str"
+        temp_str="${temp_str:1}"
+    done
+
+    # Remove the "u" if 10.4u Universal SDK is used.
+    min_str="${min_str%%u}"
+
+    system_sdk="-isystem ${selected_sdk} -mmacosx-version-min=${min_str}"
+else
+    system_sdk=" "
+fi
+
+echo " " >&2
+echo "*******************************************************************" >&2
+
+if [ -z "${system_sdk}" ]; then
+    echo "SDK Selected: None" >&2
+else
+    echo "SDK Selected: ${system_sdk}" >&2
+fi
+
+echo "To change SDK version execute 'make clean' followed by 'make'." >&2
+echo "*******************************************************************" >&2
+echo " " >&2
+
+echo ${system_sdk}
+
+