Build system: delete half-baked Cygwin support

We only support building GHC on mys2 nowadays, see
https://ghc.haskell.org/trac/ghc/wiki/Building/Preparation/Windows.

This (partially) reverts various commits from a few years ago, among which:
  * 5775d5142da227d65fb86994d363eb16841ee642
    "Add OSTYPE build-system variable, and use it"
  * 3fb8c431824aa2f3bd979e35d1a283546fcfbe74
    "Fix building libgmp on cygwin"
  * cdbb4720c424500adb57cbbef69721d0b039fa46
    "Fix cmd invocation by libffi cuild system on Windows 7 cygwin"
  * e8121501ee3549a35e954726ccfd871ac9d51f83
    "Fix dblatex and xml* tool detection on Windows"

Reviewed by: austin, Phyx

Differential Revision: https://phabricator.haskell.org/D1155

3 files changed, 4 insertions, 33 deletions

diff --git a/mk/config.mk.in b/mk/config.mk.in
index 175aa06bf2..66301c954c 100644
--- a/mk/config.mk.in
+++ b/mk/config.mk.in
@@ -165,7 +165,7 @@ GhcWithSMP := $(strip $(if $(filter YESNO, $(ArchSupportsSMP)$(GhcUnregisterised
 # Whether to include GHCi in the compiler.  Depends on whether the RTS linker
 # has support for this OS/ARCH combination.
 
-OsSupportsGHCi=$(strip $(patsubst $(TargetOS_CPP), YES, $(findstring $(TargetOS_CPP), mingw32 cygwin32 linux solaris2 freebsd dragonfly netbsd openbsd darwin kfreebsdgnu)))
+OsSupportsGHCi=$(strip $(patsubst $(TargetOS_CPP), YES, $(findstring $(TargetOS_CPP), mingw32 linux solaris2 freebsd dragonfly netbsd openbsd darwin kfreebsdgnu)))
 ArchSupportsGHCi=$(strip $(patsubst $(TargetArch_CPP), YES, $(findstring $(TargetArch_CPP), i386 x86_64 powerpc powerpc64 powerpc64le sparc sparc64 arm aarch64)))
 
 ifeq "$(OsSupportsGHCi)$(ArchSupportsGHCi)" "YESYES"
@@ -288,7 +288,7 @@ StripLibraries=NO
 #		doing object-file splitting
 
 ArchSupportsSplitObjs=$(strip $(if $(filter $(TargetArch_CPP),i386 x86_64 powerpc sparc),YES,NO))
-OsSupportsSplitObjs=$(strip $(if $(filter $(TargetOS_CPP),mingw32 cygwin32 linux darwin solaris2 freebsd dragonfly netbsd openbsd),YES,NO))
+OsSupportsSplitObjs=$(strip $(if $(filter $(TargetOS_CPP),mingw32 linux darwin solaris2 freebsd dragonfly netbsd openbsd),YES,NO))
 SplitObjsBroken = @SplitObjsBroken@
 
 SupportsSplitObjs := $(strip \
@@ -364,9 +364,6 @@ FFIIncludeDir=@FFIIncludeDir@
 # setting the TMPDIR env var would have no effect in the build tree.
 
 DEFAULT_TMPDIR		= /tmp
-ifeq "$(TARGETPLATFORM)" "i386-unknown-cygwin32"
-DEFAULT_TMPDIR		= /C/TEMP
-endif
 ifeq "$(TARGETPLATFORM)" "i386-unknown-mingw32"
 DEFAULT_TMPDIR		= /C/TEMP
 endif
diff --git a/mk/install.mk.in b/mk/install.mk.in
index d6f68abd19..da6680d6b6 100644
--- a/mk/install.mk.in
+++ b/mk/install.mk.in
@@ -146,29 +146,8 @@ INSTALL_DOC     = $(INSTALL) -m 644 $1 $2 $(call MK_INSTALL_DEST,$3)
 # Only 1 argument, the directory to create:
 INSTALL_DIR     = $(INSTALL) -m 755 -d $(call MK_INSTALL_DEST,$1)
 
-# cygwin's /bin/install doesn't set file modes correctly if the
-# destination path is a C: style path:
-#
-# $ /bin/install -c -m 644 foo /cygdrive/c/cygwin/home/ian/foo2
-# $ /bin/install -c -m 644 foo c:/cygwin/home/ian/foo3
-# $ ls -l foo*
-# -rw-r--r-- 1 ian None 0 2011-01-06 18:28 foo
-# -rw-r--r-- 1 ian None 0 2011-01-06 18:29 foo2
-# -rwxrwxrwx 1 ian None 0 2011-01-06 18:29 foo3
-#
-# This causes problems for bindisttest/checkBinaries.sh which then
-# thinks that e.g. the userguide HTML files are binaries.
-#
-# We therefore use a /cygdrive path if we are on cygwin (only)
-#   (This will make a Cygwin build run slowly 
-#    because of all those shell invocations.)
-ifeq "$(OSTYPE)" "cygwin"
-MK_INSTALL_DEST = $$(cygpath $1)
-else
 MK_INSTALL_DEST = $1
-endif
 
-#
 # runhaskell and hsc2hs are special, in that other compilers besides
 # GHC might provide them.  Systems with a package manager often come
 # with tools to manage this kind of clash, e.g. RPM's
diff --git a/mk/project.mk.in b/mk/project.mk.in
index a5fe210c12..9e45ae919b 100644
--- a/mk/project.mk.in
+++ b/mk/project.mk.in
@@ -135,24 +135,19 @@ exeext3=@exeext_target@
 soext=@soext_target@
 
 # Windows_Host=YES if on a Windows platform
-ifneq "$(findstring $(HostOS_CPP), mingw32 cygwin32)" ""
+ifneq "$(findstring $(HostOS_CPP), mingw32)" ""
 Windows_Host=YES
 else
 Windows_Host=NO
 endif
 
 # Windows_Target=YES if we are targetting a Windows platform
-ifneq "$(findstring $(TargetOS_CPP), mingw32 cygwin32)" ""
+ifneq "$(findstring $(TargetOS_CPP), mingw32)" ""
 Windows_Target=YES
 else
 Windows_Target=NO
 endif
 
-# Tell the build system what the host operating system is
-# This distinguishes "msys" and "cygwin", which are not
-# not distinguished by HOST_OS_CPP
-OSTYPE=@OSTYPE@
-
 # In case of Solaris OS, does it provide broken shared libs
 # linker or not?
 SOLARIS_BROKEN_SHLD=@SOLARIS_BROKEN_SHLD@