maint: tests: refactor gcc commands for building shared lib

* init.cfg (gcc_shared_): A new function refactored from tests.
(require_gcc_shared_): Adjust to call gcc_shared_() to build the
test library, and remove that library before the function returns.
* tests/cp/nfs-removal-race.sh: Call the new gcc_shared_().
* tests/df/no-mtab-status.sh: Likewise.
* tests/df/skip-duplicates.sh: Likewise.
* tests/ls/getxattr-speedup.sh: Likewise.
* tests/rm/r-root.sh: Likewise.

init.cfg

@@ -500,13 +500,26 @@ require_sparse_support_()
   fi
 }
 
+# Compile a shared lib using the GCC options for doing so.
+# Pass input and output file as parameters respectively.
+# Any other optional parmeters are passed to $CC.
+gcc_shared_()
+{
+  local in=$1
+  local out=$2
+  shift 2 || return 1
+
+  $CC -Wall -shared --std=gnu99 -fPIC -ldl -O2 $* "$in" -o "$out"
+}
+
 # There are a myriad of ways to build shared libs,
 # so we only consider running tests requiring shared libs,
 # on platforms that support building them as follows.
 require_gcc_shared_()
 {
-  $CC -shared -fPIC -O2 -xc -o d.so -ldl - < /dev/null 2>&1 \
+  gcc_shared_ '-' 'd.so' -xc < /dev/null 2>&1 \
     || skip_ '$CC -shared ... failed to build a shared lib'
+  rm -f d.so
 }
 
 mkfifo_or_skip_()

tests/cp/nfs-removal-race.sh

@@ -58,7 +58,7 @@ __xstat (int ver, const char *path, struct stat *st)
 EOF
 
 # Then compile/link it:
-$CC -shared -fPIC -O2 k.c -o k.so -ldl \
+gcc_shared_ k.c k.so \
   || framework_failure_ 'failed to build shared library'
 
 touch d2 || framework_failure_

tests/df/no-mtab-status.sh

@@ -45,7 +45,7 @@ struct mntent *getmntent (FILE *fp)
 EOF
 
 # Then compile/link it:
-$CC -shared -fPIC -ldl -O2 k.c -o k.so \
+gcc_shared_ k.c k.so \
   || framework_failure_ 'failed to build shared library'
 
 # Test if LD_PRELOAD works:

tests/df/skip-duplicates.sh

@@ -60,7 +60,7 @@ struct mntent *getmntent (FILE *fp)
 EOF
 
 # Then compile/link it:
-gcc --std=gnu99 -shared -fPIC -ldl -O2 k.c -o k.so \
+gcc_shared_ k.c k.so \
   || framework_failure_ 'failed to build shared library'
 
 # Test if LD_PRELOAD works:

tests/ls/getxattr-speedup.sh

@@ -48,7 +48,7 @@ ssize_t lgetxattr(const char *path, const char *name, void *value, size_t size)
 EOF
 
 # Then compile/link it:
-$CC -shared -fPIC -O2 k.c -o k.so \
+gcc_shared_ k.c k.so \
   || framework_failure_ 'failed to build shared library'
 
 # Create a few files:

tests/rm/r-root.sh

@@ -60,7 +60,7 @@ int unlinkat (int dirfd, const char *pathname, int flags)
 EOF
 
 # Then compile/link it:
-gcc -Wall --std=gnu99 -shared -fPIC -ldl -O2 k.c -o k.so \
+gcc_shared_ k.c k.so \
   || framework_failure_ 'failed to build shared library'
 
 #-------------------------------------------------------------------------------