[libc] Stub out math.h

Stub out math.h in order to include c++ headers that include it but
don't actually call any math functions.

src/libraries/libc/math.h

@@ -10,4 +10,258 @@
   * file, You can obtain one at https://mozilla.org/MPL/2.0/.
   */
 
-#error math.h is not yet implemented.
+// NOTE: libc math.h is only stubbed out currently!
+
+#define NAN 0
+#define INFINITY 0
+
+#define FP_NAN     (-1)
+#define FP_ZERO      0
+#define FP_SUBNORMAL 1
+#define FP_NORMAL    2
+#define FP_INFINITE  3
+
+#define FLT_EVAL_METHOD 0
+typedef float float_t;
+typedef double double_t;
+
+#define isinf(x)       0
+#define isnan(x)       0
+#define isnormal(x)    0
+
+#define isfinite(x)    (!isinf((x)) && !isnan((x)))
+
+#define fpclassify(x)  ((x) == 0.0 ? FP_ZERO : \
+                        isnormal((x)) ? FP_NORMAL : \
+                        isnan((x)) ? FP_NAN : \
+                        isinf((x)) ? FP_INFINITE : \
+                        FP_SUBNORMAL)
+
+
+#define signbit(x)     0
+
+
+double acos(double x);
+float acosf(float x);
+long double acosl(long double x);
+
+double asin(double x);
+float asinf(float x);
+long double asinl(long double x);
+
+double atan(double x);
+float atanf(float x);
+long double atanl(long double x);
+
+double atan2(double y, double x);
+float atan2f(float y, float x);
+long double atan2l(long double y, long double x);
+
+double cos(double x);
+float cosf(float x);
+long double cosl(long double x);
+
+double sin(double x);
+float sinf(float x);
+long double sinl(long double x);
+
+double tan(double x);
+float tanf(float x);
+long double tanl(long double x);
+
+double acosh(double x);
+float acoshf(float x);
+long double acoshl(long double x);
+
+double asinh(double x);
+float asinhf(float x);
+long double asinhl(long double x);
+
+double atanh(double x);
+float atanhf(float x);
+long double atanhl(long double x);
+
+double cosh(double x);
+float coshf(float x);
+long double coshl(long double x);
+
+double sinh(double x);
+float sinhf(float x);
+long double sinhl(long double x);
+
+double tanh(double x);
+float tanhf(float x);
+long double tanhl(long double x);
+
+double exp(double x);
+float expf(float x);
+long double expl(long double x);
+
+double exp2(double x);
+float exp2f(float x);
+long double exp2l(long double x);
+
+double expm1(double x);
+float expm1f(float x);
+long double expm1l(long double x);
+
+double frexp(double value, int *exp);
+float frexpf(float value, int *exp);
+long double frexpl(long double value, int *exp);
+
+int ilogb(double x);
+int ilogbf(float x);
+int ilogbl(long double x);
+
+double ldexp(double x, int exp);
+float ldexpf(float x, int exp);
+long double ldexpl(long double x, int exp);
+
+double log(double x);
+float logf(float x);
+long double logl(long double x);
+
+double log10(double x);
+float log10f(float x);
+long double log10l(long double x);
+
+double log1p(double x);
+float log1pf(float x);
+long double log1pl(long double x);
+
+double log2(double x);
+float log2f(float x);
+long double log2l(long double x);
+
+double logb(double x);
+float logbf(float x);
+long double logbl(long double x);
+
+double modf(double value, double *iptr);
+float modff(float value, float *iptr);
+long double modfl(long double value, long double *iptr);
+
+double scalbn(double x, int n);
+float scalbnf(float x, int n);
+long double scalbnl(long double x, int n);
+double scalbln(double x, long int n);
+float scalblnf(float x, long int n);
+long double scalblnl(long double x, long int n);
+
+double cbrt(double x);
+float cbrtf(float x);
+long double cbrtl(long double x);
+
+double fabs(double x);
+float fabsf(float x);
+long double fabsl(long double x);
+
+double hypot(double x, double y);
+float hypotf(float x, float y);
+long double hypotl(long double x, long double y);
+
+double pow(double x, double y);
+float powf(float x, float y);
+long double powl(long double x, long double y);
+
+double sqrt(double x);
+float sqrtf(float x);
+long double sqrtl(long double x);
+
+double erf(double x);
+float erff(float x);
+long double erfl(long double x);
+
+double erfc(double x);
+float erfcf(float x);
+long double erfcl(long double x);
+
+double lgamma(double x);
+float lgammaf(float x);
+long double lgammal(long double x);
+
+double tgamma(double x);
+float tgammaf(float x);
+long double tgammal(long double x);
+
+double ceil(double x);
+float ceilf(float x);
+long double ceill(long double x);
+
+double floor(double x);
+float floorf(float x);
+long double floorl(long double x);
+
+double nearbyint(double x);
+float nearbyintf(float x);
+long double nearbyintl(long double x);
+
+double rint(double x);
+float rintf(float x);
+long double rintl(long double x);
+
+long int lrint(double x);
+long int lrintf(float x);
+long int lrintl(long double x);
+long long int llrint(double x);
+long long int llrintf(float x);
+long long int llrintl(long double x);
+
+double round(double x);
+float roundf(float x);
+long double roundl(long double x);
+
+long int lround(double x);
+long int lroundf(float x);
+long int lroundl(long double x);
+long long int llround(double x);
+long long int llroundf(float x);
+long long int llroundl(long double x);
+
+double trunc(double x);
+float truncf(float x);
+long double truncl(long double x);
+
+double fmod(double x, double y);
+float fmodf(float x, float y);
+long double fmodl(long double x, long double y);
+
+double remainder(double x, double y);
+float remainderf(float x, float y);
+long double remainderl(long double x, long double y);
+
+double remquo(double x, double y, int *quo);
+float remquof(float x, float y, int *quo);
+long double remquol(long double x, long double y, int *quo);
+
+double copysign(double x, double y);
+float copysignf(float x, float y);
+long double copysignl(long double x, long double y);
+
+double nan(const char *tag);
+float nanf(const char *tagp);
+long double nanl(const char *tagp);
+
+double nextafter(double x, double y);
+float nextafterf(float x, float y);
+long double nextafterl(long double x, long double y);
+
+double nexttoward(double x, long double y);
+float nexttowardf(float x, long double y);
+long double nexttowardl(long double x, long double y);
+
+double fdim(double x, double y);
+float fdimf(float x, float y);
+long double fdiml(long double x, long double y);
+
+double fmax(double x, double y);
+float fmaxf(float x, float y);
+long double fmaxl(long double x, long double y);
+
+double fmin(double x, double y);
+float fminf(float x, float y);
+long double fminl(long double x, long double y);
+
+double fma(double x, double y, double z);
+float fmaf(float x, float y, float z);
+long double fmal(long double x, long double y, long double z);

src/libraries/libc/string/strncat.cpp

@@ -10,7 +10,6 @@
 
 #include <string.h>
 #include <stddef.h>
-#include <__j6libc/copy.h>
 
 char *strncat(char * restrict s1, const char * restrict s2, size_t n) {
     if (!s1 || !s2 || !n)