fix compilation on Debian 7 (no git -C) (#18427)

* fix compilation on Debian 7 (no git -C)

* address review

* allow specify branch for testing unmerged csources

* temporarily change csources checkout parameters for testing

* Update tools/deps.nim

Co-authored-by: Timothee Cour <timothee.cour2@gmail.com>

* fix failure

* Update config/build_config.txt

* set proper git branch/hash

Co-authored-by: Timothee Cour <timothee.cour2@gmail.com>
Co-authored-by: Andreas Rumpf <rumpf_a@web.de>

tools/ci_generate.nim

@@ -61,7 +61,7 @@ SET nim_csources=bin\nim_csources_%nim_csourcesHash%.exe
 echo "building from csources: %nim_csources%"
 
 if not exist %nim_csourcesDir% (
-  git clone -q --depth 1 %nim_csourcesUrl% %nim_csourcesDir%
+  git clone -q --depth 1 -b %nim_csourcesBranch% %nim_csourcesUrl% %nim_csourcesDir%
 )
 
 if not exist %nim_csources% (

tools/deps.nim

@@ -28,8 +28,13 @@ proc cloneDependency*(destDirBase: string, url: string, commit = commitHead,
     # from failing
     execRetry fmt"git clone -q {url} {destDir2}"
   if isGitRepo(destDir):
-    execRetry fmt"git -C {destDir2} fetch -q"
-    exec fmt"git -C {destDir2} checkout -q {commit}"
+    let oldDir = getCurrentDir()
+    setCurrentDir(destDir2)
+    try:
+      execRetry "git fetch -q"
+      exec fmt"git checkout -q {commit}"
+    finally:
+      setCurrentDir(oldDir)
   elif allowBundled:
     discard "this dependency was bundled with Nim, don't do anything"
   else:

tools/niminst/makefile.nimf

@@ -25,7 +25,8 @@ endif
 
 ifeq ($(uos),linux)
   myos = linux
-  LDFLAGS += -ldl -lm
+  # add -lrt to avoid "undefined reference to `clock_gettime'" with glibc<2.17
+  LDFLAGS += -ldl -lm -lrt
 endif
 ifeq ($(uos),dragonfly)
   myos = freebsd