Change include style to use system includes

The libcper header files in `libcper` are installed to
`usr/include/libcper`. Use that system includes in `libcper` source
instead of using the project includes.

Change-Id: I596edc2c754dae4829844f535a1e34caa246fb43
Signed-off-by: Thu Nguyen <thu@os.amperecomputing.com>
diff --git a/tests/base64_test.cpp b/tests/base64_test.cpp
index 3fcb3af..6040c00 100644
--- a/tests/base64_test.cpp
+++ b/tests/base64_test.cpp
@@ -1,4 +1,4 @@
-#include "base64.h"
+#include <libcper/base64.h>
 
 #include "gtest/gtest.h"
 #include "gmock/gmock.h"
diff --git a/tests/ir-tests.cpp b/tests/ir-tests.cpp
index 0146cac..5041a23 100644
--- a/tests/ir-tests.cpp
+++ b/tests/ir-tests.cpp
@@ -8,11 +8,11 @@
 #include "gtest/gtest.h"
 #include "test-utils.hpp"
 #include <json.h>
-#include "../cper-parse.h"
-#include "../json-schema.h"
-#include "../generator/cper-generate.h"
-#include "../sections/cper-section.h"
-#include "../generator/sections/gen-section.h"
+#include <libcper/cper-parse.h>
+#include <libcper/json-schema.h>
+#include <libcper/generator/cper-generate.h>
+#include <libcper/sections/cper-section.h>
+#include <libcper/generator/sections/gen-section.h>
 
 /*
 * Test templates.
diff --git a/tests/meson.build b/tests/meson.build
index abfc497..68eb1f3 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -21,7 +21,7 @@
 
 sources = ['ir-tests.cpp', 'test-utils.cpp', 'base64_test.cpp']
 
-test_include_dirs = ['.', '..']
+test_include_dirs = ['.', '../include']
 
 cper_tests = executable(
     'cper-tests',
diff --git a/tests/test-utils.cpp b/tests/test-utils.cpp
index c508e8d..e16413c 100644
--- a/tests/test-utils.cpp
+++ b/tests/test-utils.cpp
@@ -8,8 +8,8 @@
 #include <cstdlib>
 #include "test-utils.hpp"
 
-#include "BaseTypes.h"
-#include "../generator/cper-generate.h"
+#include <libcper/BaseTypes.h>
+#include <libcper/generator/cper-generate.h>
 
 //Returns a ready-for-use memory stream containing a CPER record with the given sections inside.
 FILE *generate_record_memstream(const char **types, UINT16 num_types,
diff --git a/tests/test-utils.hpp b/tests/test-utils.hpp
index af9390e..38e24a7 100644
--- a/tests/test-utils.hpp
+++ b/tests/test-utils.hpp
@@ -2,7 +2,7 @@
 #define CPER_IR_TEST_UTILS_H
 
 extern "C" {
-#include "BaseTypes.h"
+#include <libcper/BaseTypes.h>
 }
 
 FILE *generate_record_memstream(const char **types, UINT16 num_types,