Rename CMake find_package helpers to avoid developer warnings

| CMake Warning (dev) at /usr/share/cmake-3.18/Modules/FindPackageHandleStandardArgs.cmake:273 (message):
|   The package name passed to `find_package_handle_standard_args` (Berkeley)
|   does not match the name of the calling package (BerkeleyDB).  This can lead
|   to problems in calling code that expects `find_package` result variables
|   (e.g., `_FOUND`) to follow a certain pattern.
| Call Stack (most recent call first):
|   CMake/FindBerkeleyDB.cmake:57 (find_package_handle_standard_args)
|   CMakeLists.txt:83 (find_package)
| This warning is for project developers.  Use -Wno-dev to suppress it.

And indeed, we checked for BERKLEY_DB_FOUND which was not defined so our
HAVE_BDB was not set – just that it is never used, so it wasn't noticed.

1 files changed, 59 insertions, 0 deletions

diff --git a/CMake/FindBerkeley.cmake b/CMake/FindBerkeley.cmake
new file mode 100644
index 000000000..a6215d728
--- /dev/null
+++ b/CMake/FindBerkeley.cmake
@@ -0,0 +1,59 @@
+# - Try to find Berkeley DB
+# Once done this will define
+#
+#  BERKELEY_FOUND - system has Berkeley DB
+#  BERKELEY_INCLUDE_DIRS - the Berkeley DB include directory
+#  BERKELEY_LIBRARIES - Link these to use Berkeley DB
+#  BERKELEY_DEFINITIONS - Compiler switches required for using Berkeley DB
+
+# Copyright (c) 2006, Alexander Dymo, <adymo@kdevelop.org>
+# Copyright (c) 2016, Julian Andres Klode <jak@debian.org>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+# 3. The name of the author may not be used to endorse or promote products
+#    derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+# We need NO_DEFAULT_PATH here, otherwise CMake helpfully picks up the wrong
+# db.h on BSD systems instead of the Berkeley DB one.
+find_path(BERKELEY_INCLUDE_DIRS db.h
+  ${CMAKE_INSTALL_FULL_INCLUDEDIR}/db5
+  /usr/local/include/db5
+  /usr/include/db5
+
+  ${CMAKE_INSTALL_FULL_INCLUDEDIR}/db4
+  /usr/local/include/db4
+  /usr/include/db4
+
+  ${CMAKE_INSTALL_FULL_INCLUDEDIR}
+  /usr/local/include
+  /usr/include
+
+  NO_DEFAULT_PATH
+)
+
+find_library(BERKELEY_LIBRARIES NAMES db db-5)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(Berkeley "Could not find Berkeley DB >= 4.1" BERKELEY_INCLUDE_DIRS BERKELEY_LIBRARIES)
+# show the BERKELEY_INCLUDE_DIRS and BERKELEY_LIBRARIES variables only in the advanced view
+mark_as_advanced(BERKELEY_INCLUDE_DIRS BERKELEY_LIBRARIES)