add plpgsql (#198)

contrib/plpgsql/Dockerfile

@@ -0,0 +1,29 @@
+ARG PG_VERSION=15
+FROM quay.io/coredb/c-builder:pg${PG_VERSION}
+USER root
+
+# Extension build dependencies
+RUN apt-get update && apt-get install -y \
+	build-essential \
+	libreadline-dev \
+	zlib1g-dev \
+	flex \
+	bison \
+	libxml2-dev \
+	libxslt-dev \
+	libssl-dev \
+	libxml2-utils \
+	xsltproc \
+	ccache
+
+# Clone repository
+RUN git clone https://github.com/postgres/postgres.git 
+
+ARG PG_VERSION=15
+
+RUN cd postgres && \
+    git fetch origin REL_${PG_VERSION}_STABLE && \
+	git checkout REL_${PG_VERSION}_STABLE && \
+	./configure && \
+	cd src/pl/plpgsql && \
+	make

contrib/plpgsql/Trunk.toml

@@ -0,0 +1,21 @@
+[extension]
+name = "plpgsql"
+version = "1.0.0"
+repository = "https://github.com/postgres/postgres/tree/master/src/pl/plpgsql"
+license = "PostgreSQL"
+description = "The PL/Pgsql procedural language for PostgreSQL."
+homepage = "https://www.postgresql.org"
+documentation = "https://www.postgresql.org/docs/current/plpgsql.html"
+categories = ["procedural_languages"]
+
+[build]
+postgres_version = "15"
+platform = "linux/amd64"
+dockerfile = "Dockerfile"
+install_command = """
+    make -C postgres/src/pl/plpgsql install
+    set -x
+    mv /usr/local/pgsql/share/extension/* /usr/share/postgresql/15/extension
+    mv /usr/local/pgsql/lib/* /usr/lib/postgresql/15/lib
+"""
+