As in haskell#3974 and haskell#4105, but also dedupe PD.includeDirs…

… and `PD.extraLibDirs`.

Should help with big invocations as found in
NixOS/nixpkgs#41340.

Cabal/ChangeLog.md

@@ -1,7 +1,41 @@
-### 2.2.0.1 [Mikhail Glushenkov](mailto:mikhail.glushenkov@gmail.com) March 2018
+# 2.4.0.0 (current development version)
+
+  * Added `BlockArguments` to `KnownExtension` (#5101).
+  * Added `NumericUnderscores` to `KnownExtension` (#5130).
+  * `buildDepends` is removed from `PackageDescription`. It had long been
+    uselessly hanging about as top-level build-depends already got put
+    into per-component condition trees anyway. Now it's finally been put
+    out of its misery (#4383).
+  * Added `Eta` to `CompilerFlavor` and to known compilers.
+  * `cabal haddock` now generates per-component documentation (#5226).
+  * Allow `**` wildcards in `data-files`, `extra-source-files` and
+    `extra-doc-files`. These allow a limited form of recursive
+    matching, and require `cabal-version: 3.0`.
+
+    Wildcard syntax errors (misplaced `*`, etc) are also now detected
+    by `cabal check`.
+
+    `FileGlob`, `parseFileGlob`, `matchFileGlob` and `matchDirFileGlob`
+    have beem moved from `Distribution.Simple.Utils` to a new file,
+    `Distribution.Simple.Glob` and `FileGlob` has been made abstract.
+
+    (#5284, #3178, et al.)
+  * Fixed `cxx-options` and `cxx-sources` buildinfo fields for
+    separate compilation of C++ source files to correctly build and link
+    non-library components (#5309).
+  * Reduced warnings generated by hsc2hs and c2hs when `cxx-options` field
+    is present in a component.
+  * `cabal check` now warns if `-j` is used in `ghc-options` in a Cabal
+    file. (#5277)
+  * Cabal now dedupliates more `-I` and `-L` and flags to avoid `E2BIG`
+    (#5356)
+
+----
+
+## 2.2.0.1 (current 2.2 development version)
+
+  * Fix `checkPackageFiles` for relative directories ([#5206](https://github.com/haskell/cabal/issues/5206))
 
-  * Fix `checkPackageFiles` for relative directories
-    ([#5206](https://github.com/haskell/cabal/issues/5206)).
 
 # 2.2.0.0 [Mikhail Glushenkov](mailto:mikhail.glushenkov@gmail.com) March 2018
 

Cabal/Distribution/Simple/Configure.hs

@@ -1726,12 +1726,12 @@ checkForeignDeps pkg lbi verbosity =
                      -- should NOT be glomming everything together.)
                      ++ [ "-I" ++ buildDir lbi </> "autogen" ]
                      -- `configure' may generate headers in the build directory
-                     ++ [ "-I" ++ buildDir lbi </> dir | dir <- collectField PD.includeDirs
+                     ++ [ "-I" ++ buildDir lbi </> dir | dir <- ordNub (collectField PD.includeDirs)
                                                        , not (isAbsolute dir)]
                      -- we might also reference headers from the packages directory.
-                     ++ [ "-I" ++ baseDir lbi </> dir | dir <- collectField PD.includeDirs
+                     ++ [ "-I" ++ baseDir lbi </> dir | dir <- ordNub (collectField PD.includeDirs)
                                                       , not (isAbsolute dir)]
-                     ++ [ "-I" ++ dir | dir <- collectField PD.includeDirs
+                     ++ [ "-I" ++ dir | dir <- ordNub (collectField PD.includeDirs)
                                       , isAbsolute dir]
                      ++ ["-I" ++ baseDir lbi]
                      ++ collectField PD.cppOptions
@@ -1753,7 +1753,7 @@ checkForeignDeps pkg lbi verbosity =
                         | dep <- deps
                         , opt <- Installed.ccOptions dep ]
 
-        commonLdArgs  = [ "-L" ++ dir | dir <- collectField PD.extraLibDirs ]
+        commonLdArgs  = [ "-L" ++ dir | dir <- ordNub (collectField PD.extraLibDirs) ]
                      ++ collectField PD.ldOptions
                      ++ [ "-L" ++ dir
                         | dir <- ordNub [ dir