add syntax cIncludeDir "$projpath/include"; do not use recursive search paths; add test tests/tnimterop_cpp.nim

tests/tnimterop_c.nim

@@ -0,0 +1,46 @@
+import nimterop/cimport
+
+cDebug()
+
+cDefine("FORCE")
+cIncludeDir "$projpath/include"
+cAddSearchDir "$projpath/include"
+cCompile cSearchPath("test.c")
+cImport cSearchPath "test.h"
+
+doAssert TEST_INT == 512
+doAssert TEST_FLOAT == 5.12
+doAssert TEST_HEX == 0x512
+
+var
+  pt: PRIMTYPE
+  ct: CUSTTYPE
+
+  s: STRUCT1
+  s2: STRUCT2
+  s3: STRUCT3
+  s4: STRUCT4
+
+  e: ENUM
+  e2: ENUM2 = enum5
+
+  vptr: VOIDPTR
+  iptr: INTPTR
+
+pt = 3
+ct = 4
+
+s.field1 = 5
+s2.field1 = 6
+s3.field1 = 7
+
+e = enum1
+e2 = enum4
+
+doAssert test_call_int() == 5
+doAssert test_call_int_param(5).field1 == 5
+doAssert test_call_int_param2(5, s2).field1 == 11
+doAssert test_call_int_param3(5, s).field1 == 10
+doAssert test_call_int_param4(e) == e2
+
+cAddStdDir()