Fix: GSstreamer build script path resolution (#1263)

Using relative paths for build script made it
prone to fail and to produce unexpected results
when executed from different working directories.

Add a check to ensure the script always runs from
its own directory.

Fixes: 12098ba

Author: DawidWesierski4

.github/scripts/setup_environment.sh

@@ -182,6 +182,7 @@ function setup_ubuntu_install_dependencies() {
 		echo "Installing GStreamer dependencies"
 		apt install -y \
 			gstreamer1.0-plugins-base \
+			libgstreamer-plugins-base1.0-dev \
 			gstreamer1.0-plugins-good \
 			gstreamer1.0-tools \
 			gstreamer1.0-libav \

ecosystem/gstreamer_plugin/build.sh

@@ -5,6 +5,11 @@ set -euo pipefail
 BUILD_DIR="builddir"
 DEBUG=false
 
+SCRIPT_NAME=$(basename "${BASH_SOURCE[0]}")
+SCRIPT_PATH=$(readlink -qe "${BASH_SOURCE[0]}")
+SCRIPT_FOLDER=${SCRIPT_PATH/$SCRIPT_NAME/}
+cd "${SCRIPT_FOLDER}" || exit 1
+
 # Parse command-line arguments
 for arg in "$@"; do
 	case "$arg" in