use pigenhole-ldap from alpine repo

Dockerfile

@@ -1,20 +1,13 @@
 FROM registry.gitlab.com/thallian/docker-confd-env:master
 
-ADD i_zero.patch /usr/include/dovecot/i_zero.patch
-
-RUN apk add --no-cache dovecot dovecot-ldap libressl ssmtp ca-certificates g++ openldap-dev dovecot-dev make tar && \
-    cd /usr/include/dovecot && \
-    patch -p1 < i_zero.patch && \
-    rm /usr/include/dovecot/i_zero.patch && \
-    mkdir /tmp/pigeonhole && \
-    wget -qO- https://pigeonhole.dovecot.org/releases/2.2/dovecot-2.2-pigeonhole-0.4.18.tar.gz | tar -xz -C /tmp/pigeonhole --strip 1 && \
-    cd /tmp/pigeonhole && \
-    ./configure --with-ldap=yes --with-dovecot=/usr/lib/dovecot  && \
-    make && make install && \
-    rm -r /tmp/pigeonhole && \
-    apk del g++ openldap-dev dovecot-dev make tar
-
-WORKDIR /
+RUN apk add --no-cache \
+    dovecot \
+    dovecot-ldap \
+    dovecot-pigeonhole-plugin \
+    dovecot-pigeonhole-plugin-ldap \
+    libressl \
+    ssmtp \
+    ca-certificates
 
 RUN addgroup -g 2222 access
 RUN addgroup dovecot access

i_zero.patch

@@ -1,12 +0,0 @@
-diff --git a/macros.h b/macros.h
-index 566c176..ebbf480 100644
---- a/macros.h
-+++ b/macros.h
-@@ -240,4 +240,7 @@
- #  define STATIC_ARRAY
- #endif
-
-+#define i_zero(p) memset(p, 0, sizeof(*(p)))
-+#define i_zero_safe(p) safe_memset(p, 0, sizeof(*(p)))
-+
- #endif