RPM: remove dependency on the which utility

It is not necessary to know the full path to a program. Instead use the
'type' shell builtin (part of POSIX) to detect availability.

Change-Id: Id68b298625d389a1f7843f52f56312bf81d97b80
Reviewed-on: https://code.wireshark.org/review/31540
Reviewed-by: Peter Wu <peter@lekensteyn.nl>

.gitlab-ci.yml

@@ -76,7 +76,6 @@ rpm-centos-7:
   image: centos:7
   script:
     - yum -y install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
-    - yum install -y which
     - tools/rpm-setup.sh --install-optional -y
     - mkdir build
     - cd build
@@ -86,7 +85,7 @@ rpm-centos-7:
 rpm-opensuse-42.3:
   image: opensuse:42.3
   script:
-    - zypper --non-interactive install which update-desktop-files
+    - zypper --non-interactive install update-desktop-files
     - tools/rpm-setup.sh --install-optional ruby
     - gem install asciidoctor
     - mkdir build
@@ -98,7 +97,6 @@ rpm-fedora-28:
   image: fedora:28
   script:
     - dnf upgrade -y
-    - dnf install -y which
     - tools/rpm-setup.sh --install-optional -y
     - mkdir build
     - cd build

packaging/rpm/wireshark.spec.in

@@ -293,7 +293,7 @@ cmake3 \
 %if %{with ninja}
 # Older RPM-based distributions used ninja-build in order to prevent a collision with
 # the Ninja IRC client: https://bugzilla.redhat.com/show_bug.cgi?id=1166135
-NINJA=$(which ninja || which ninja-build)
+NINJA=$(type ninja >/dev/null 2>&1 && echo ninja || echo ninja-build)
 $NINJA
 %else
 # Suggestion: put this in your ~/.rpmmacros (without the hash sign, of course):
@@ -307,7 +307,7 @@ rm -rf $RPM_BUILD_ROOT
 cd build
 %endif
 %if %{with ninja}
-NINJA=$(which ninja || which ninja-build)
+NINJA=$(type ninja >/dev/null 2>&1 && echo ninja || echo ninja-build)
 DESTDIR=$RPM_BUILD_ROOT $NINJA install
 %if %{with guides}
 DESTDIR=$RPM_BUILD_ROOT $NINJA install_guides

tools/rpm-setup.sh

@@ -71,9 +71,11 @@ ADDITIONAL_LIST="libnl3-devel \
 	rpm-build"
 
 # Guess which package manager we will use
-PM=`which zypper 2> /dev/null ||
-which dnf 2> /dev/null ||
-which yum 2> /dev/null`
+for PM in zypper dnf yum ''; do
+	if type "$PM" >/dev/null 2>&1; then
+		break
+	fi
+done
 
 if [ -z $PM ]
 then
@@ -82,14 +84,14 @@ then
 fi
 
 case $PM in
-	*/zypper)
+	zypper)
 		PM_OPT="--non-interactive"
 		PM_SEARCH="search -x --provides"
 		;;
-	*/dnf)
+	dnf)
 		PM_SEARCH="info"
 		;;
-	*/yum)
+	yum)
 		PM_SEARCH="info"
 		;;
 esac