tools build: Remove leftover libcap tests that prevents fast path feature detection from working

I noticed that the fast path feature detection was failing:

  $ cat /tmp/build/perf-tools-next/feature/test-all.make.output
  /usr/bin/ld: cannot find -lcap: No such file or directory
  collect2: error: ld returned 1 exit status
  $

The patch removing the dependency (Fixes tag below) didn't remove the
detection of libcap, and as the fast path feature detection (test-all.c)
had -lcap in its Makefile link list of libraries to link, it was failing
when libcap-devel is not available, fix it by removing those leftover
files.

Fixes: e25ebda7 ("perf cap: Tidy up and improve capability testing")
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/Zs-gjOGFWtAvIZit@x1Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/build/feature/Makefile

@@ -25,7 +25,6 @@ FILES=                                          \
          test-libbfd-liberty-z.bin              \
          test-cplus-demangle.bin                \
          test-cxa-demangle.bin                  \
-         test-libcap.bin			\
          test-libelf.bin                        \
          test-libelf-getphdrnum.bin             \
          test-libelf-gelf_getnote.bin           \
@@ -112,7 +111,7 @@ all: $(FILES)
 __BUILD = $(CC) $(CFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.c,$(@F)) $(LDFLAGS)
   BUILD = $(__BUILD) > $(@:.bin=.make.output) 2>&1
   BUILD_BFD = $(BUILD) -DPACKAGE='"perf"' -lbfd -ldl
-  BUILD_ALL = $(BUILD) -fstack-protector-all -O2 -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lelf -lslang $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl -lz -llzma -lzstd -lcap
+  BUILD_ALL = $(BUILD) -fstack-protector-all -O2 -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lelf -lslang $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl -lz -llzma -lzstd
 
 __BUILDXX = $(CXX) $(CXXFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.cpp,$(@F)) $(LDFLAGS)
   BUILDXX = $(__BUILDXX) > $(@:.bin=.make.output) 2>&1
@@ -140,9 +139,6 @@ $(OUTPUT)test-fortify-source.bin:
 $(OUTPUT)test-bionic.bin:
 	$(BUILD)
 
-$(OUTPUT)test-libcap.bin:
-	$(BUILD) -lcap
-
 $(OUTPUT)test-libelf.bin:
 	$(BUILD) -lelf
 

tools/build/feature/test-libcap.c

-// SPDX-License-Identifier: GPL-2.0
-#include <sys/capability.h>
-#include <linux/capability.h>
-
-int main(void)
-{
-	cap_flag_value_t val;
-	cap_t caps = cap_get_proc();
-
-	if (!caps)
-		return 1;
-
-	if (cap_get_flag(caps, CAP_SYS_ADMIN, CAP_EFFECTIVE, &val) != 0)
-		return 1;
-
-	if (cap_free(caps) != 0)
-		return 1;
-
-	return 0;
-}