There are several Gettext compilation errors with C#.

/bin/sh ../csharpcomp.sh -O -g -o msgfmt.net.exe ../../../../../source/gettext-0.18.2/gettext-tools/src/msgfmt.cs
error CS1504: Не удалось открыть исходный файл "t:\MinGW-w64\mingw\libs_build\gettext\build\gettext-0.18.2-x32\shared\gettext-tools\src\msgfmt.cs"
        ("Не удается найти указанный файл. ")
make[3]: * [msgfmt.net.exe] Error 1

Translation: "error CS1504: Can't open source file ... ("Source file not found")"
Seems that csc is ignoring path, when path contain forward slashes and not quoted. When filename is quoted, then files just can't be found, even if copied to build directory.
Workaround is the same as for 0.18.1.1: just copy all *.cs files from source to build directories.
As csc is used only with Msys, this can be fixed like this:

pushd "${filename%/*}" 1> /dev/null
winfile="${pwd -W}/${filename##*/}"
winfile="${winfile//\//\\}"
command ... ... "$winfile"
popd 1> /dev/null

Other problem arises when trying to 'make' only in 'gettext-tools' directory. Referenced "GNU.Gettext.dll" not found as "GNU.Gettext.dll" was not build.