diff --git a/pkgs/applications/gis/grass/default.nix b/pkgs/applications/gis/grass/default.nix
index 420f57bb93f..c1b7841dc58 100644
--- a/pkgs/applications/gis/grass/default.nix
+++ b/pkgs/applications/gis/grass/default.nix
@@ -3,6 +3,8 @@
 , proj, gdal, geos, sqlite, postgresql, libmysqlclient, python2Packages, libLAS, proj-datumgrid
 }:
 
+let inherit (stdenv) lib; in
+
 stdenv.mkDerivation rec {
   name = "grass";
   version = "7.6.1";
@@ -42,7 +44,7 @@ stdenv.mkDerivation rec {
     "--with-postgres-libs=${postgresql.lib}/lib/"
     # it complains about missing libmysqld but doesn't really seem to need it
     "--with-mysql"
-    "--with-mysql-includes=${libmysqlclient}/include/mysql"
+    "--with-mysql-includes=${lib.getDev libmysqlclient}/include/mysql"
     "--with-mysql-libs=${libmysqlclient}/lib/mysql"
     "--with-blas"
     "--with-liblas=${libLAS}/bin/liblas-config"
diff --git a/pkgs/applications/networking/irc/communi/default.nix b/pkgs/applications/networking/irc/communi/default.nix
index 6cb6f2c2ef6..f3a840e23d0 100644
--- a/pkgs/applications/networking/irc/communi/default.nix
+++ b/pkgs/applications/networking/irc/communi/default.nix
@@ -19,16 +19,17 @@ stdenv.mkDerivation rec {
 
   preConfigure = ''
     export QMAKEFEATURES=${libcommuni}/features
-    qmakeFlags="$qmakeFlags \
-      COMMUNI_INSTALL_PREFIX=$out \
-      COMMUNI_INSTALL_BINS=$out/bin \
-      COMMUNI_INSTALL_PLUGINS=$out/lib/communi/plugins \
-      COMMUNI_INSTALL_ICONS=$out/share/icons/hicolor \
-      COMMUNI_INSTALL_DESKTOP=$out/share/applications \
-      COMMUNI_INSTALL_THEMES=$out/share/communi/themes
-    "
   '';
 
+  qmakeFlags = [
+    "COMMUNI_INSTALL_PREFIX=${placeholder "out"}"
+    "COMMUNI_INSTALL_BINS=${placeholder "out"}/bin"
+    "COMMUNI_INSTALL_PLUGINS=${placeholder "out"}/lib/communi/plugins"
+    "COMMUNI_INSTALL_ICONS=${placeholder "out"}/share/icons/hicolor"
+    "COMMUNI_INSTALL_DESKTOP=${placeholder "out"}/share/applications"
+    "COMMUNI_INSTALL_THEMES=${placeholder "out"}/share/communi/themes"
+  ];
+
   postInstall = stdenv.lib.optionalString stdenv.isLinux ''
     substituteInPlace "$out/share/applications/communi.desktop" \
       --replace "/usr/bin" "$out/bin"
diff --git a/pkgs/development/libraries/gdal/2.4.0.nix b/pkgs/development/libraries/gdal/2.4.0.nix
index 201bec30e22..d3505679e4d 100644
--- a/pkgs/development/libraries/gdal/2.4.0.nix
+++ b/pkgs/development/libraries/gdal/2.4.0.nix
@@ -39,7 +39,7 @@ stdenv.mkDerivation rec {
     "--with-poppler=${poppler.dev}" # optional
     "--with-libz=${zlib.dev}"       # optional
     "--with-pg=${postgresql}/bin/pg_config"
-    "--with-mysql=${libmysqlclient}/bin/mysql_config"
+    "--with-mysql=${getDev libmysqlclient}/bin/mysql_config"
     "--with-geotiff=${libgeotiff.dev}"
     "--with-sqlite3=${sqlite.dev}"
     "--with-spatialite=${libspatialite}"
diff --git a/pkgs/development/libraries/gdal/default.nix b/pkgs/development/libraries/gdal/default.nix
index 72135f1a62d..1295a100232 100644
--- a/pkgs/development/libraries/gdal/default.nix
+++ b/pkgs/development/libraries/gdal/default.nix
@@ -50,7 +50,7 @@ stdenv.mkDerivation rec {
     "--with-poppler=${poppler.dev}" # optional
     "--with-libz=${zlib.dev}" # optional
     "--with-pg=yes" # since gdal 3.0 doesn't use ${postgresql}/bin/pg_config
-    "--with-mysql=${libmysqlclient}/bin/mysql_config"
+    "--with-mysql=${getDev libmysqlclient}/bin/mysql_config"
     "--with-geotiff=${libgeotiff}"
     "--with-sqlite3=${sqlite.dev}"
     "--with-spatialite=${libspatialite}"
diff --git a/pkgs/development/libraries/glpk/default.nix b/pkgs/development/libraries/glpk/default.nix
index 8c5a50c43d1..124e03baee1 100644
--- a/pkgs/development/libraries/glpk/default.nix
+++ b/pkgs/development/libraries/glpk/default.nix
@@ -1,6 +1,7 @@
 { stdenv
 , fetchurl
 , fetchpatch
+, libmysqlclient
 # Excerpt from glpk's INSTALL file:
 # This feature allows the exact simplex solver to use the GNU MP
 # bignum library. If it is disabled, the exact simplex solver uses the
@@ -21,9 +22,11 @@ stdenv.mkDerivation rec {
     sha256 = "040sfaa9jclg2nqdh83w71sv9rc1sznpnfiripjdyr48cady50a2";
   };
 
-  buildInputs = stdenv.lib.optionals withGmp [
-    gmp
-  ];
+  buildInputs =
+    [ libmysqlclient
+    ] ++ stdenv.lib.optionals withGmp [
+      gmp
+    ];
 
   configureFlags = stdenv.lib.optionals withGmp [
     "--with-gmp"
@@ -47,6 +50,13 @@ stdenv.mkDerivation rec {
     })
   ];
 
+  postPatch =
+    # Do not hardcode the include path for libmysqlclient.
+    ''
+      substituteInPlace configure \
+        --replace '-I/usr/include/mysql' '$(mysql_config --include)'
+    '';
+
   doCheck = true;
 
   meta = {
diff --git a/pkgs/development/libraries/libdbi-drivers/default.nix b/pkgs/development/libraries/libdbi-drivers/default.nix
index d321d7d650a..871c9f97167 100644
--- a/pkgs/development/libraries/libdbi-drivers/default.nix
+++ b/pkgs/development/libraries/libdbi-drivers/default.nix
@@ -28,7 +28,7 @@ stdenv.mkDerivation rec {
     "--with-dbi-libdir=${libdbi}/lib"
   ] ++ optionals (libmysqlclient != null) [
     "--with-mysql"
-    "--with-mysql-incdir=${libmysqlclient}/include/mysql"
+    "--with-mysql-incdir=${getDev libmysqlclient}/include/mysql"
     "--with-mysql-libdir=${libmysqlclient}/lib/mysql"
   ] ++ optionals (sqlite != null) [
     "--with-sqlite3"
diff --git a/pkgs/development/libraries/opendbx/default.nix b/pkgs/development/libraries/opendbx/default.nix
index 16ec6a5c110..954e6cc6b66 100644
--- a/pkgs/development/libraries/opendbx/default.nix
+++ b/pkgs/development/libraries/opendbx/default.nix
@@ -1,5 +1,7 @@
 { stdenv, fetchurl, readline, libmysqlclient, postgresql, sqlite }:
 
+let inherit (stdenv.lib) getDev; in
+
 stdenv.mkDerivation rec {
   name = "opendbx-1.4.6";
 
@@ -9,7 +11,7 @@ stdenv.mkDerivation rec {
   };
 
   preConfigure = ''
-    export CPPFLAGS="-I${libmysqlclient}/include/mysql"
+    export CPPFLAGS="-I${getDev libmysqlclient}/include/mysql"
     export LDFLAGS="-L${libmysqlclient}/lib/mysql -L${postgresql}/lib"
     configureFlagsArray=(--with-backends="mysql pgsql sqlite3")
   '';
diff --git a/pkgs/development/lua-modules/overrides.nix b/pkgs/development/lua-modules/overrides.nix
index 6416d59a71e..8e77c190247 100644
--- a/pkgs/development/lua-modules/overrides.nix
+++ b/pkgs/development/lua-modules/overrides.nix
@@ -169,7 +169,7 @@ with super;
   luadbi-mysql = super.luadbi-mysql.override({
     extraVariables = {
       # Can't just be /include and /lib, unfortunately needs the trailing 'mysql'
-      MYSQL_INCDIR="${pkgs.libmysqlclient}/include/mysql";
+      MYSQL_INCDIR="${pkgs.libmysqlclient.dev}/include/mysql";
       MYSQL_LIBDIR="${pkgs.libmysqlclient}/lib/mysql";
     };
     buildInputs = [
diff --git a/pkgs/servers/sql/mariadb/connector-c/default.nix b/pkgs/servers/sql/mariadb/connector-c/default.nix
index fb41890d432..8c71514dfba 100644
--- a/pkgs/servers/sql/mariadb/connector-c/default.nix
+++ b/pkgs/servers/sql/mariadb/connector-c/default.nix
@@ -18,6 +18,8 @@ stdenv.mkDerivation {
     inherit sha256;
   };
 
+  outputs = [ "out" "dev" ];
+
   cmakeFlags = [
     "-DMARIADB_UNIX_ADDR=/run/mysqld/mysqld.sock"
     "-DWITH_CURL=ON"
@@ -25,6 +27,12 @@ stdenv.mkDerivation {
     "-DWITH_MYSQLCOMPAT=ON"
   ];
 
+  postPatch = ''
+    substituteInPlace mariadb_config/mariadb_config.c.in \
+      --replace '@CMAKE_SYSROOT@@CMAKE_INSTALL_PREFIX@/@INSTALL_INCLUDEDIR@' "$dev/include" \
+      --replace '@CMAKE_SYSROOT@@CMAKE_INSTALL_PREFIX@/@INSTALL_LIBDIR@' "$out/lib/mariadb"
+  '';
+
   # The cmake setup-hook uses $out/lib by default, this is not the case here.
   preConfigure = optionalString stdenv.isDarwin ''
     cmakeFlagsArray+=("-DCMAKE_INSTALL_NAME_DIR=$out/lib/mariadb")
@@ -36,12 +44,16 @@ stdenv.mkDerivation {
 
   enableParallelBuilding = true;
 
+  postInstall = ''
+    moveToOutput bin/mariadb_config "$dev"
+  '';
+
   postFixup = ''
-    ln -sv mariadb_config $out/bin/mysql_config
+    ln -sv mariadb_config $dev/bin/mysql_config
     ln -sv mariadb $out/lib/mysql
-    ln -sv mariadb $out/include/mysql
-    ln -sv mariadb_version.h $out/include/mariadb/mysql_version.h
-    ln -sv libmariadb.pc $out/lib/pkgconfig/mysqlclient.pc
+    ln -sv mariadb $dev/include/mysql
+    ln -sv mariadb_version.h $dev/include/mariadb/mysql_version.h
+    ln -sv libmariadb.pc $dev/lib/pkgconfig/mysqlclient.pc
   '';
 
   meta = {
diff --git a/pkgs/tools/backup/mydumper/default.nix b/pkgs/tools/backup/mydumper/default.nix
index 88a72762990..611e543ca6c 100644
--- a/pkgs/tools/backup/mydumper/default.nix
+++ b/pkgs/tools/backup/mydumper/default.nix
@@ -1,6 +1,8 @@
 { stdenv, fetchFromGitHub, cmake, pkgconfig
 , glib, zlib, pcre, libmysqlclient, libressl }:
 
+let inherit (stdenv.lib) getDev; in
+
 stdenv.mkDerivation rec {
   version = "0.9.5";
   pname = "mydumper";
@@ -16,6 +18,8 @@ stdenv.mkDerivation rec {
 
   buildInputs = [ glib zlib pcre libmysqlclient libressl ];
 
+  cmakeFlags = [ "-DMYSQL_INCLUDE_DIR=${getDev libmysqlclient}/include/mysql" ];
+
   meta = with stdenv.lib; {
     description = ''High-perfomance MySQL backup tool'';
     homepage = "https://github.com/maxbube/mydumper";
diff --git a/pkgs/tools/networking/kea/default.nix b/pkgs/tools/networking/kea/default.nix
index 386a3ae280a..1637827f66e 100644
--- a/pkgs/tools/networking/kea/default.nix
+++ b/pkgs/tools/networking/kea/default.nix
@@ -1,6 +1,8 @@
 { stdenv, fetchurl, autoreconfHook, pkgconfig, openssl, botan2, log4cplus
 , boost, python3, postgresql, libmysqlclient, gmp, bzip2 }:
 
+let inherit (stdenv) lib; in
+
 stdenv.mkDerivation rec {
   pname = "kea";
   version = "1.5.0-P1";
@@ -20,7 +22,7 @@ stdenv.mkDerivation rec {
   configureFlags = [
     "--localstatedir=/var"
     "--with-pgsql=${postgresql}/bin/pg_config"
-    "--with-mysql=${libmysqlclient}/bin/mysql_config"
+    "--with-mysql=${lib.getDev libmysqlclient}/bin/mysql_config"
   ];
 
   nativeBuildInputs = [ autoreconfHook pkgconfig ];
diff --git a/pkgs/tools/networking/mailutils/default.nix b/pkgs/tools/networking/mailutils/default.nix
index 9cf5f91cd6d..adcd2f1dc13 100644
--- a/pkgs/tools/networking/mailutils/default.nix
+++ b/pkgs/tools/networking/mailutils/default.nix
@@ -18,9 +18,6 @@ stdenv.mkDerivation rec {
       */Makefile{.in,.am}
     sed -i 's:/usr/lib/mysql:${libmysqlclient}/lib/mysql:' configure.ac
     sed -i 's/0\.18/0.19/' configure.ac
-    sed -i -e 's:mysql/mysql.h:mysql.h:' \
-           -e 's:mysql/errmsg.h:errmsg.h:' \
-      sql/mysql.c
   '';
 
   nativeBuildInputs = [
diff --git a/pkgs/tools/networking/pmacct/default.nix b/pkgs/tools/networking/pmacct/default.nix
index ffecbfcaf42..2bb6f373727 100644
--- a/pkgs/tools/networking/pmacct/default.nix
+++ b/pkgs/tools/networking/pmacct/default.nix
@@ -19,7 +19,7 @@ assert withSQLite -> sqlite != null;
 assert withPgSQL -> postgresql != null;
 assert withMysql -> libmysqlclient != null;
 
-let inherit (stdenv.lib) optional; in
+let inherit (stdenv.lib) getDev optional optionalString; in
 
 stdenv.mkDerivation rec {
   version = "1.7.5";
@@ -40,6 +40,9 @@ stdenv.mkDerivation rec {
     ++ optional withPgSQL postgresql
     ++ optional withMysql [ libmysqlclient zlib ];
 
+  MYSQL_CONFIG =
+    optionalString withMysql "${getDev libmysqlclient}/bin/mysql_config";
+
   configureFlags = [
     "--with-pcap-includes=${libpcap}/include"
   ] ++ optional withJansson "--enable-jansson"