diff --git a/headers/posix/math.h b/headers/posix/math.h
index 480258e8aa..1e34e0832a 100644
--- a/headers/posix/math.h
+++ b/headers/posix/math.h
@@ -41,6 +41,13 @@ extern char __infinity[];
 #define	M_SQRT2		1.41421356237309504880	/* sqrt(2) */
 #define	M_SQRT1_2	0.70710678118654752440	/* 1/sqrt(2) */
 
+#ifndef PI
+#define PI  M_PI
+#endif
+#ifndef PI2
+#define PI2  M_PI_2
+#endif
+
 #define	MAXFLOAT	((float)3.40282346638528860e+38)
 extern int signgam;
 
diff --git a/headers/private/libroot/trig.h b/headers/private/libroot/trig.h
index 5ab6a1dba2..e5b7d84df6 100644
--- a/headers/private/libroot/trig.h
+++ b/headers/private/libroot/trig.h
@@ -39,23 +39,29 @@ vc(thresh, 2.6117239648121182150E-1 ,b863,3f85,6ea0,6b02, -1, .85B8636B026EA0)
 vc(PIo4,   7.8539816339744830676E-1 ,0fda,4049,68c2,a221,  0, .C90FDAA22168C2)
 vc(PIo2,   1.5707963267948966135E0  ,0fda,40c9,68c2,a221,  1, .C90FDAA22168C2)
 vc(PI3o4,  2.3561944901923449203E0  ,cbe3,4116,0e92,f999,  2, .96CBE3F9990E92)
-vc(PI,     3.1415926535897932270E0  ,0fda,4149,68c2,a221,  2, .C90FDAA22168C2)
-vc(PI2,    6.2831853071795864540E0  ,0fda,41c9,68c2,a221,  3, .C90FDAA22168C2)
+
+// no, we declare PI and PI2 as a macros in <math.h>
+//vc(PI,     3.1415926535897932270E0  ,0fda,4149,68c2,a221,  2, .C90FDAA22168C2)
+//vc(PI2,    6.2831853071795864540E0  ,0fda,41c9,68c2,a221,  3, .C90FDAA22168C2)
 
 ic(thresh, 2.6117239648121182150E-1 , -2, 1.0B70C6D604DD4)
 ic(PIo4,   7.8539816339744827900E-1 , -1, 1.921FB54442D18)
 ic(PIo2,   1.5707963267948965580E0  ,  0, 1.921FB54442D18)
 ic(PI3o4,  2.3561944901923448370E0  ,  1, 1.2D97C7F3321D2)
-ic(PI,     3.1415926535897931160E0  ,  1, 1.921FB54442D18)
-ic(PI2,    6.2831853071795862320E0  ,  2, 1.921FB54442D18)
+
+// no, we declare PI and PI2 as a macros in <math.h>
+//ic(PI,     3.1415926535897931160E0  ,  1, 1.921FB54442D18)
+//ic(PI2,    6.2831853071795862320E0  ,  2, 1.921FB54442D18)
 
 #ifdef vccast
 #define	thresh	vccast(thresh)
 #define	PIo4	vccast(PIo4)
 #define	PIo2	vccast(PIo2)
 #define	PI3o4	vccast(PI3o4)
-#define	PI	vccast(PI)
-#define	PI2	vccast(PI2)
+
+// no, we declare PI and PI2 as a macros in <math.h>
+//#define	PI	vccast(PI)
+//#define	PI2	vccast(PI2)
 #endif
 
 #ifdef national
diff --git a/src/kernel/libroot/posix/math/atan2.c b/src/kernel/libroot/posix/math/atan2.c
index ea789a4f9c..9c1045f9fc 100644
--- a/src/kernel/libroot/posix/math/atan2.c
+++ b/src/kernel/libroot/posix/math/atan2.c
@@ -105,6 +105,7 @@
  * shown.
  */
 
+#include <math.h>
 #include <mathimpl.h>
 
 vc(athfhi, 4.6364760900080611433E-1  ,6338,3fed,da7b,2b0d,  -1, .ED63382B0DDA7B)
@@ -113,7 +114,10 @@ vc(PIo4,   7.8539816339744830676E-1  ,0fda,4049,68c2,a221,   0, .C90FDAA22168C2)
 vc(at1fhi, 9.8279372324732906796E-1  ,985e,407b,b4d9,940f,   0, .FB985E940FB4D9)
 vc(at1flo,-3.5540295636764633916E-18 ,1edc,a383,eaea,34d6, -57,-.831EDC34D6EAEA)
 vc(PIo2,   1.5707963267948966135E0   ,0fda,40c9,68c2,a221,   1, .C90FDAA22168C2)
-vc(PI,     3.1415926535897932270E0   ,0fda,4149,68c2,a221,   2, .C90FDAA22168C2)
+
+// no, we declare PI as a macro in <math.h>
+//vc(PI,     3.1415926535897932270E0   ,0fda,4149,68c2,a221,   2, .C90FDAA22168C2)
+
 vc(a1,     3.3333333333333473730E-1  ,aaaa,3faa,ab75,aaaa,  -1, .AAAAAAAAAAAB75)
 vc(a2,    -2.0000000000017730678E-1  ,cccc,bf4c,946e,cccd,  -2,-.CCCCCCCCCD946E)
 vc(a3,     1.4285714286694640301E-1  ,4924,3f12,4262,9274,  -2, .92492492744262)
@@ -133,7 +137,10 @@ ic(PIo4,   7.8539816339744827900E-1  ,  -1,  1.921FB54442D18)
 ic(at1fhi, 9.8279372324732905408E-1  ,  -1,  1.F730BD281F69B)
 ic(at1flo,-2.4407677060164810007E-17 , -56, -1.C23DFEFEAE6B5)
 ic(PIo2,   1.5707963267948965580E0   ,   0,  1.921FB54442D18)
-ic(PI,     3.1415926535897931160E0   ,   1,  1.921FB54442D18)
+
+// no, we declare PI as a macro in <math.h>
+//ic(PI,     3.1415926535897931160E0   ,   1,  1.921FB54442D18)
+
 ic(a1,     3.3333333333333942106E-1  ,  -2,  1.55555555555C3)
 ic(a2,    -1.9999999999979536924E-1  ,  -3, -1.9999999997CCD)
 ic(a3,     1.4285714278004377209E-1  ,  -3,  1.24924921EC1D7)
@@ -153,7 +160,10 @@ ic(a11,    1.6438029044759730479E-2  ,  -6,  1.0D52174A1BB54)
 #define	at1fhi	vccast(at1fhi)
 #define	at1flo	vccast(at1flo)
 #define	PIo2	vccast(PIo2)
-#define	PI	vccast(PI)
+
+// no, we declare PI as a macro in <math.h>
+//#define	PI	vccast(PI)
+
 #define	a1	vccast(a1)
 #define	a2	vccast(a2)
 #define	a3	vccast(a3)