Clean-up for src/bin/sage-env, move src/bin/sage-clone-source, src/bin/sage-sdist to build/bin

[mkoeppe]

We remove some unused environment variables from the sage runtime environment.

Part of Meta-ticket #21707: Split sage-env into 5 to clean up sage configuration

Depends on #21559
Depends on #29929
Depends on #30088

CC: @orlitzky @kiwifb @antonio-rojas @vbraun

Component: build

Author: Matthias Koeppe

Branch/Commit: 7c91fb4

Reviewer: John Palmieri, François Bissey

Issue created by migration from https://trac.sagemath.org/ticket/29825

[mkoeppe]

Branch: u/mkoeppe/clean_up_for_src_bin_sage_env

[mkoeppe]

Commit: 20b81cc

[mkoeppe]

Description changed:

--- 
+++ 
@@ -1 +1,2 @@
+We remove some unused environment variables from the sage runtime environment.
 

[mkoeppe]

Author: Matthias Koeppe

[mkoeppe]

New commits:

a61ce1e	src/bin/sage-env-config.in: Do not export CONFIGURED_CC etc. and SAGE_PKG_CONFIG_PATH; only used in sage-env
f0e37ad	build/make/install: Move SAGE_SPKG_SCRIPTS here from src/bin/sage-env; only used during build
20b81cc	src/bin/sage-env: Do not set SAGE_PKGCONFIG; only use in build/ and already set in build/make/install

[mkoeppe]

Description changed:

--- 
+++ 
@@ -1,2 +1,3 @@
 We remove some unused environment variables from the sage runtime environment.
 
+Part of Meta-ticket #21707: Split sage-env into 5 to clean up sage configuration

[jhpalmieri]

Reviewer: John Palmieri

[jhpalmieri]

comment:6

Looks okay to me.

[mkoeppe]

comment:7

Thanks!

[vbraun]

Changed branch from u/mkoeppe/clean_up_for_src_bin_sage_env to 20b81cc

[vbraun]

Changed commit from 20b81cc to none