Compile libmpdec-dev from sources

The package is not available on recent PHP 8.x images which are based on
Debian Bookworm.

See docker-library/php#1416.

README.md

@@ -377,11 +377,11 @@ Also, if you already have Docker installed, you can run the tests in a docker co
 ./dockerfile.sh | docker build -t msgpack -
 ```
 
-The command above will create a container named `msgpack` with PHP 8.1 runtime. You may change the default runtime 
+The command above will create a container named `msgpack` with PHP 8.2 runtime. You may change the default runtime 
 by defining the `PHP_IMAGE` environment variable:
 
 ```sh
-PHP_IMAGE='php:8.0-cli' ./dockerfile.sh | docker build -t msgpack -
+PHP_IMAGE='php:8.1-cli' ./dockerfile.sh | docker build -t msgpack -
 ```
 
 > *See a list of various images [here](https://hub.docker.com/_/php).*

dockerfile.sh

@@ -1,19 +1,37 @@
 #!/usr/bin/env bash
 
 if [[ -z "$PHP_IMAGE" ]]; then
-    PHP_IMAGE='php:8.1-cli'
+    PHP_IMAGE='php:8.2-cli'
 fi
 
 RUN_CMDS=''
-if [[ -z "$EXT_DISABLE_DECIMAL" || "0" == "$EXT_DISABLE_DECIMAL" || "false" == "$EXT_DISABLE_DECIMAL" ]] ; then
-  RUN_CMDS="$RUN_CMDS && \\\\\n    apt-get install -y libmpdec-dev"
-  RUN_CMDS="$RUN_CMDS && \\\\\n    pecl install decimal && docker-php-ext-enable decimal"
-fi
-
 if [[ -n "$COVERAGE_FILE" ]]; then
     RUN_CMDS="$RUN_CMDS && \\\\\n    pecl install pcov && docker-php-ext-enable pcov"
 fi
 
+if [[ -z "$EXT_DISABLE_DECIMAL" || "0" == "$EXT_DISABLE_DECIMAL" || "false" == "$EXT_DISABLE_DECIMAL" ]] ; then
+    # PHP 8.x images are based on Debian Bookworm, where the libmpdec-dev package
+    # is not available, therefore the package has to be compiled from sources.
+    # See https://github.com/docker-library/php/pull/1416.
+
+    MPDEC_RELEASE_NAME="mpdecimal-2.5.1"
+    MPDEC_URL="https://www.bytereef.org/software/mpdecimal/releases/$MPDEC_RELEASE_NAME.tar.gz"
+    MPDEC_SHA256_SUM="9f9cd4c041f99b5c49ffb7b59d9f12d95b683d88585608aa56a6307667b2b21f"
+    MPDEC_TMP_DIR="/tmp/$MPDEC_RELEASE_NAME"
+    MPDEC_TMP_ARCHIVE="$MPDEC_TMP_DIR/$MPDEC_RELEASE_NAME.tar.gz"
+
+    RUN_CMDS="$RUN_CMDS\\n\\nRUN"
+    RUN_CMDS="$RUN_CMDS mkdir -p $MPDEC_TMP_DIR"
+    RUN_CMDS="$RUN_CMDS && \\\\\n    cd $MPDEC_TMP_DIR"
+    RUN_CMDS="$RUN_CMDS && \\\\\n    curl -LO $MPDEC_URL"
+    RUN_CMDS="$RUN_CMDS && \\\\\n    echo \"$MPDEC_SHA256_SUM $MPDEC_TMP_ARCHIVE\" | sha256sum --check --status -"
+    RUN_CMDS="$RUN_CMDS && \\\\\n    tar xf $MPDEC_TMP_ARCHIVE"
+    RUN_CMDS="$RUN_CMDS && \\\\\n    cd $MPDEC_RELEASE_NAME"
+    RUN_CMDS="$RUN_CMDS && \\\\\n    ./configure && make && make install"
+    RUN_CMDS="$RUN_CMDS && \\\\\n    rm -rf $MPDEC_TMP_DIR"
+    RUN_CMDS="$RUN_CMDS && \\\\\n    pecl install decimal && docker-php-ext-enable decimal"
+fi
+
 COMPOSER_REMOVE=''
 
 echo -e "