Remove which dependency from startup scripts

compiler/cli/bin/kotlin

@@ -16,4 +16,7 @@
 
 export KOTLIN_RUNNER=1
 
-"$(dirname "$(which "$0")")"/kotlinc "$@"
+DIR="${BASH_SOURCE[0]%/*}"
+: ${DIR:="."}
+
+"${DIR}"/kotlinc "$@"

compiler/cli/bin/kotlinc-js

@@ -16,4 +16,7 @@
 
 export KOTLIN_COMPILER=org.jetbrains.kotlin.cli.js.K2JSCompiler
 
-"$(dirname "$(which "$0")")"/kotlinc "$@"
+DIR="${BASH_SOURCE[0]%/*}"
+: ${DIR:="."}
+
+"${DIR}"/kotlinc "$@"

compiler/cli/bin/kotlinc-jvm

@@ -14,4 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"$(dirname "$(which "$0")")"/kotlinc "$@"
+DIR="${BASH_SOURCE[0]%/*}"
+: ${DIR:="."}
+
+"${DIR}"/kotlinc "$@"