packages: Add 'package-development-inputs'.

* guix/packages.scm (package-development-inputs): New procedure.
* guix/scripts/environment.scm (package-environment-inputs): Use it.
* tests/packages.scm ("package-development-inputs")
("package-development-inputs, cross-compilation"): New tests.
* doc/guix.texi (package Reference): Document it.

1 files changed, 10 insertions, 0 deletions

diff --git a/guix/packages.scm b/guix/packages.scm
index e5a9d08bce..b99689b9a4 100644
--- a/guix/packages.scm
+++ b/guix/packages.scm
@@ -153,6 +153,7 @@
             bag-transitive-host-inputs
             bag-transitive-build-inputs
             bag-transitive-target-inputs
+            package-development-inputs
             package-closure
 
             default-guile
@@ -1070,6 +1071,15 @@ dependencies are known to build on SYSTEM."
                  (%current-system (bag-system bag)))
     (transitive-inputs (bag-target-inputs bag))))
 
+(define* (package-development-inputs package
+                                     #:optional (system (%current-system))
+                                     #:key target)
+  "Return the list of inputs required by PACKAGE for development purposes on
+SYSTEM.  When TARGET is true, return the inputs needed to cross-compile
+PACKAGE from SYSTEM to TRIPLET, where TRIPLET is a triplet such as
+\"aarch64-linux-gnu\"."
+  (bag-transitive-inputs (package->bag package system target)))
+
 (define* (package-closure packages #:key (system (%current-system)))
   "Return the closure of PACKAGES on SYSTEM--i.e., PACKAGES and the list of
 packages they depend on, recursively."