tools build: Add test to check if slang.h is in /usr/include/slang/

A few odd old distros (rhel5, 6, yeah, lots of those out in use, in many
cases we want to use upstream perf on it) have the slang header files in
/usr/include/slang/, so add a test that will be performed only when
test-all.c (the one with the most common sane settings) fails, either
because we're in one of these odd distros with slang/slang.h or because
something else failed (say libelf is not present).

So for the common case nothing changes, no additional test is performed.

Next step is to check in perf the result of these tests.

Cc: Adrian Hunter <[email protected]>
Cc: Florian Fainelli <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Fixes: 1955c8cf5e ("perf tools: Don't hardcode host include path for libslang")
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

tools/build/Makefile.feature

@@ -53,6 +53,7 @@ FEATURE_TESTS_BASIC :=                  \
         libpython                       \
         libpython-version               \
         libslang                        \
+        libslang-include-subdir         \
         libcrypto                       \
         libunwind                       \
         pthread-attr-setaffinity-np     \
@@ -114,7 +115,6 @@ FEATURE_DISPLAY ?=              \
          numa_num_possible_cpus \
          libperl                \
          libpython              \
-         libslang               \
          libcrypto              \
          libunwind              \
          libdw-dwarf-unwind     \

tools/build/feature/Makefile

@@ -31,6 +31,7 @@ FILES=                                          \
          test-libpython.bin                     \
          test-libpython-version.bin             \
          test-libslang.bin                      \
+         test-libslang-include-subdir.bin       \
          test-libcrypto.bin                     \
          test-libunwind.bin                     \
          test-libunwind-debug-frame.bin         \
@@ -184,6 +185,9 @@ $(OUTPUT)test-libaudit.bin:
 $(OUTPUT)test-libslang.bin:
 	$(BUILD) -lslang
 
+$(OUTPUT)test-libslang-include-subdir.bin:
+	$(BUILD) -lslang
+
 $(OUTPUT)test-libcrypto.bin:
 	$(BUILD) -lcrypto
 

tools/build/feature/test-libslang-include-subdir.c

@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <slang/slang.h>
+
+int main(void)
+{
+	return SLsmg_init_smg();
+}