Add an 'osmo' prefix to the 'gapk' binary

This is a common practice of all Osmocom executables
to have an 'osmo' prefix. Let's follow this here too.
diff --git a/.gitignore b/.gitignore
index 93316ad..6288340 100644
--- a/.gitignore
+++ b/.gitignore
@@ -36,7 +36,7 @@
 libgsmhr/refsrc
 
 # final executables
-src/gapk
+src/osmo-gapk
 
 # temporary/backup files
 *.*~
diff --git a/contrib/benchmark.sh b/contrib/benchmark.sh
index 0148667..0e86876 100755
--- a/contrib/benchmark.sh
+++ b/contrib/benchmark.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-GAPK=./src/gapk
+GAPK=./src/osmo-gapk
 PCMFILE=$1
 BASE=`basename $PCMFILE`
 
diff --git a/src/Makefile.am b/src/Makefile.am
index 93bdfa1..c38f2fe 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -75,16 +75,16 @@
 	$(NULL)
 
 # libosmogapk representative application
-bin_PROGRAMS = gapk
+bin_PROGRAMS = osmo-gapk
 
-gapk_SOURCES = \
+osmo_gapk_SOURCES = \
 	main.c \
 	$(NULL)
 
-gapk_LDFLAGS = \
+osmo_gapk_LDFLAGS = \
 	$(LIBOSMOCORE_LIBS) \
 	$(NULL)
 
-gapk_LDADD = \
+osmo_gapk_LDADD = \
 	$(top_builddir)/src/libosmogapk.la \
 	$(NULL)
diff --git a/test/common.sh b/test/common.sh
index 591be3a..5fded94 100644
--- a/test/common.sh
+++ b/test/common.sh
@@ -1,13 +1,13 @@
 # directory containing the reference files for comparing against
 REFDIR=./ref-files
 
-if [ -f ../src/gapk ]; then
-	GAPK=../src/gapk
-elif [ -f `which gapk` ]; then
-	GAPK=`which gapk`
+if [ -f ../src/osmo-gapk ]; then
+	GAPK=../src/osmo-gapk
+elif [ -f `which osmo-gapk` ]; then
+	GAPK=`which osmo-gapk`
 else
 	exit 1
 fi
-echo Using gapk found at $GAPK
+echo Using osmo-gapk found at $GAPK
 
 FORMATS="amr-efr gsm racal-hr racal-fr racal-efr ti-hr ti-fr ti-efr rtp-efr rtp-hr-etsi rtp-hr-ietf"