Merge bitcoin#10245: Minor fix in build documentation for FreeBSD 11

0611bc3 Minor fix in build documentation for FreeBSD 11 (Shigeya Suzuki)

Tree-SHA512: d0e0b66868e4a988e1fa121b9c7b2877b77e2b3c7a9d7a6220c9e16cf0d6817786e9020aeba19dfa2cbc07b2fbba12f2afefc442e762a7d00292bde7515ef880

doc/build-unix.md

@@ -107,11 +107,34 @@ A list of additional configure flags can be displayed with:
 
 Building on FreeBSD
 --------------------
-
 (TODO, this is untested, please report if it works and if changes to this documentation are needed)
 
-Building on FreeBSD is basically the same as on Linux based systems, with the difference that you have to use `gmake`
-instead of `make`.
+(Updated as of FreeBSD 11.0)
+
+Clang is installed by default as `cc` compiler, this makes it easier to get
+started than on [OpenBSD](build-openbsd.md). Installing dependencies:
+
+    pkg install autoconf automake libtool pkgconf
+    pkg install boost-libs openssl libevent
+    pkg install gmake
+
+You need to use GNU make (`gmake`) instead of `make`.
+(`libressl` instead of `openssl` will also work)
+
+For the wallet (optional):
+
+    pkg install db5
+
+This will give a warning "configure: WARNING: Found Berkeley DB other
+than 4.8; wallets opened by this build will not be portable!", but as FreeBSD never
+had a binary release, this may not matter. If backwards compatibility
+with 4.8-built Dash Core is needed follow the steps under "Berkeley DB" above.
+
+Then build using:
+
+    ./autogen.sh
+    ./configure --with-incompatible-bdb BDB_CFLAGS="-I/usr/local/include/db5" BDB_LIBS="-L/usr/local/lib -ldb_cxx-5"
+    gmake
 
 *Note on debugging*: The version of `gdb` installed by default is [ancient and considered harmful](https://wiki.freebsd.org/GdbRetirement).
 It is not suitable for debugging a multi-threaded C++ program, not even for getting backtraces. Please install the package `gdb` and